Kiosk No. 6 (K6)


Kiosk No. 6 - known as the K6 - was introduced in the UK in 1936 (Mark 2 was introduced in 1939) to commemorate the Silver Jubilee of the coronation of King George V.  The 'Jubilee Kiosk', as it became known, was once again designed by Sir Giles Gilbert Scott and approved by the Fine Arts Commission.  It was similar in appearance to Kiosk No. 2, the main difference being that the vertical bars in the windows and door were spaced further apart to improve visibility.

Post Office red was chosen as the kiosks colour, although not without objections from some quarters on aesthetic grounds it nevertheless received the approval of the Royal Fine Arts Commission and that approval was supported by the Councils for the Preservation of Rural England, Wales and Scotland, thus placing the Post Office in a particularly strong position to justify the choice made.

The K2 had not penetrated far outside London, but the 'Jubilee' model became the first genuinely standard kiosk and was installed all over the country.

Under the "Jubilee Concession", introduced as part of that year's celebrations, kiosks were to be provided in every town or village with a post office, regardless of cost.  As a result of this scheme over 8,000 new kiosks were installed, adding impetus to the spread of the K6.

In the following year, the "Tercentenary Concession" was introduced: if a local authority committed to paying £4 a year, then the normal subscription, for five years then the Post Office would install a kiosk on request almost anywhere.  This scheme remained in force until 1949 and led to almost another thousand K6s being introduced.  The "Rural Allocation Scheme" was introduced to replace it: kiosks were allocated to rural areas and installed where recommended by a rural local authority, whether likely to prove profitable or not.

The kiosks were made of the best grey cast iron with glazing in 26oz glass.  The total weight was 13.5cwt.

The Mark 1 did not last long and was quickly updated to the Mark 2 which had more secure window fixings and coin box  mounting points. It was found coin box could be easily prised off in the Mark 1 kiosks and the Mark 2 was made with threaded holes in the back panel for the coin box fixing bolts.

An easy way to identify the two Marks is to look at the two cable entry holes at the bottom of the rear panel.  The Mark one has symmetrical holes, whilst the Mark two has asymmetrical holes.

The K6 Kiosk can be found with three different crowns.  The Tudor Crown of George V (the Kings Crown) and this crown can be identified by it's flattened bottom, whilst the Tudor Crown of King George VI had more shape to the base of the crown.

The MacFarlane/Saracen foundry used the flatter crown for Marks 1 and 2.  Macdowall Steven also used this (flatter) crown but they only manufactured Mark 1.  The fuller Crown was used by Lion and Carron for Marks 1 & 2.  Bratt Colbran also used this (fuller) crown but they only manufactured Mark 1.

After 1953 the crown on the kiosk was changed to the St Edwards Crown (Queens Crown).  Between 1955 and 1965 the K6 kiosks were produced with a slot where the crown was located so that in England the St Edwards Crown were fitted and in Scotland the Royal Crown of Scotland.  See below for further information.

The K6 was the most prolific kiosk in the UK and it's growth was:-
1925 - 1,000
1930 - 8,000
1935 - 19,000
1940 - 35,000
1950 - 44,000
1960 - 65,000
1970 - 70,000
1980 - 73,000

The 'Jubilee Kiosk' is perhaps the best remembered example of Gilbert Scott's work (with the possible exception of Liverpool Cathedral) and is to this day fondly regarded as a typical British landmark.  K6s survived the introduction of Nos. 7 and 8, but during the 1980s and early 1990s were frequently replaced with the modern KX 100 - 400 series of payphone booths.  Thousands of old K6 kiosks were sold off at public auctions.  Some were scrapped, but many more were put to a variety of imaginative and bizarre uses in private hands.  However, the Department of the Environment and English Heritage worked with BT to identify kiosks, including more than 1,000 K6s, worthy of listing as being of special architectural and historical interest, mainly near existing listed buildings or in attractive town and country locations.

The Mark 2 differed in respects to the glazing frames being retained by brass studs instead of screws, two knock outs in the rear panel and four tapped studs on the rear panel for fixing the mechanism (theft prevention).  In the early 1970's the glazing practice was changed - the glass, cast glazing frame and studs were replaced with moulded Perspex glazing panels held in place by steel pins secured with serrated washers.

The Kiosk was also illuminated at night.  This was achieved by a timer connected to the mains electric supply.  The timers could be fitted with one of five solar dials, each solar dial was designed for an area of the UK due to the dusk and dawn being at different times depending on the location.  On the introduction of the fluorescent light fitting in the early 1970's the time switches were removed and the lights remained illuminated 24 hours a day.

Some of the above taken from BT archives

Addendum to above
It appears that when BT went mad and started reinstalling recycled red boxes again, even though most of the suppliers of the units knew the difference, the contractors who did the installations didn't get the message (or possibly ignored it) and so Scottish models ended up being installed in London.  One Kiosk, to be found in Craven St, WC2, actually has two different crowns fitted!

More ironically though, the flip side of this confusion was that Scotland got kiosks that it shouldn't have too.  Many examples can be found in Central Edinburgh and on the Royal Mile.

In the years 2017 and 2018 British Telecoms wrote to UK Councils enquiring if they wished to purchase most of the Telephone Kiosks in their respective areas.  The price per kiosk was £1 and BT would pay the electric bill for a period of time.  Many Councils have now purchased Kiosks and are using them for a variety of purposes.

The crowns were never highlighted with paint until somebody at BT decided to paint them gold in the 21st Century!

Average weight of castings - 13¼cwt.

Uses Hinges, Brass No. 2 on the door (6" x 3").

Specification - D1140

Drawings (Mark 2)
Sill Frame - 60907
Corner pillars and Transoms - 60906
Crown Panels - 60908
Dome - 60907
Side & Back Panels and glazing framework - 60905
Frames, Glazing No. 1 and 2 - 90783
Assembly - 60904
Glasses no 47 and 47A - 60909

The K6 Kiosk was superseded by the K8 Kiosk

K6 Installation details

Click here for a pictorial list of K6 Kiosks

Click here for K6 prototypes

Preliminary sketches (not verified but dated 1935) - Sketch 1, Sketch 2 and Sketch 3.


The following is taken from
Specification D1140Q
Dated 1956

castings shall be of sound grey cast iron, clean and free from blowholes, distortion, and all surface and other defects.  They shall be well dressed or fettled and free from chill.  The phosphorous content of the iron shall not normally exceed 1.0%.  All joints shall be carefully faced and fitted.  Screw holes shall be accurately drilled using a template where practicable.  Except for the inside surface of the dome, the clean castings shall be painted prior to inspection with priming paint complying with Specification No. M 267, or with other approved primer, to provide a suitable surface for subsequent coats of paint and prevent the onset of rusting before the finishing coats of paint can be applied.  The inside surface of the dome shall be primed with a zinc paint complying with Specification No. M 285.  Two thin, well bushed coats shall be applied.

door shall be of teak, or other approved hardwood, finished to the size shown in Drawing No. 60905; the bottom rail shall be wrought from the solid. The joints shall be mortised and tenoned, and cemented with "BEETLE CEMENT A" and "BEETLE HARDENER No. 15", used as instructed by the manufacturers of the cement. The woodwork shall be knotted and primed with the same primer as the castings before firing the glazing framework. This frame shall be properly bedded in putty and screwed up.

upper portion of the back panel of each kiosk shall be marked on the inside with the P.O. stock list code, the approved code letters allocated to the manufacturer and the mark number. e.g. 6A FHB/2.  The type letter shall be stencilled in white paint but the other markings shall be cast in 0.5in. characters.  The letters FHB are typical only and the particular manufacturer's approved code letters shall be substituted in accordance with Specification No. D1000.  In addition each separate casting shall have the manufacturer's code letters cast on in such a manner that they appear on the inside of the kiosk when erected.  Also, the sections shall be stencilled with serial numbers as indicated on Diagram EC1324 (shown below) for guidance during erection.

Window Frames
24 x Frames, Glazing No. 1.
48 x Frames, Glazing No. 2.

The kiosk shall be manufactured in four types A, B, C and D as indicated in Diagram EC1324.  In addition, two types of crown ornament shall be made to Drawing 60908.  Four "St. Edward's Crown" ornaments shall be supplied with each kiosk unless the delivery order calls for Scottish Crowns, in which case four "Royal Crown of Scotland" ornaments shall be substituted.  Instructions as to the quantities of each type of kiosk and of crown ornament, will be issued to the manufacturer at suitable intervals during the course of the contract.

Diagram EC1324

KIT No. 35
All the screws, bolts and other small parts needed to erect the kiosk
constitute what is known as a Kit No. 35.  The items in this kit are listed in Appendix A and should be supplied in a suitable bag.  An inventory of the parts set out in the form indicated in Appendix A shall be enclosed in a waterproof envelope and placed in the bag.

Contents of Kit No. 35

All screws and bolt have B.S.W. threads and unless otherwise are mild steel.  Diameter quoted before length.

No. Description Use
4 Mild steel plates 3" x 3" x 1/4" Levelling plates for sill
4 1/2" X 3" Hex. Conical Hd. Levelling screws for sill
8 3/8" X 1.1/4" Rd. Hd. Corner pillars to base
2 1/2" x 1.1/2" Rd. Hd. Door transom to corner pillars
61 5/16" x 1" CSK. Hd.

Transoms to corner pillars and sides
Sides to corner pi
Crown panels to corner pillars

9 3/8" x 1.1/4" Rd. Hd. Sides to base
4 3/16" x 5/8" CSK. Hd. Crown panels to transoms
8 5/16" x 1" Rd. Hd. Dome to crown panels
15 Screws, Wood Brass No. 14. 1.1/4" Hinges to door
6 1/4" X 1/2" CSK. Hd. Brass

Hinges to corner pillar -2 per hinge

15 1/4" x 5/8" CSK. Hd. Brass

9 for bingos to corner pillar
3 per hinge
6 tor Sha
ckles No. 5 to corner pillar

3 1/4" X  7/16" CSK. Hd. Shackle No. 5 (upper) to door
3 Screws, Wood Brass No. 12. 1.1/4" Shackle No. 5 (lower) to door
4 1/4 x 5/8" Hex. hd. Door closer to transom
2 Black cup head bolts 1/4" x 1.3/4" with Hex. nut Door closer arm to door
4 Screws Wood No. 6. 3/4", CSK. hd.Stainless Steel Handle to door
16 Glazing Pins, Brass, 1/8" x 3/4" Preliminary securing of Glasses No. 47 or No. 47A
4 1/4" x 1.1/4" CSK. Hd. Brass

Hardwood block to back panel
(E.L- CO's cut-out)

8 3/16" x 5/16" Rd. Hd. Brass Cable cleats to back panel
(lighting circuit)
3 3/16" x 5/8" Rd. Hd. Brass E. L. pendant to dome
2 1/4" x 3/4" CSK. Hd. Brass Time switch to back panel
2 3/16" x 3/4" Hex. Hd.

Capping Steel, No. 6 to back panel


Crowns (Used on Mark 2 Kiosks)

Original Mark 2 Kiosks had the Tudor Crown of George VI but, unlike the Mark 1, the design had more shape to the base of the crown.  In 1953 the crown became the St Edward's Crown.

In the early 1950s the UK Cabinet decided that the Scottish Crown should replace the Royal Cypher and the St Edward's Crown on mail vans and new letterboxes in Scotland.  In 1955 it was decided that kiosks No. 6 should be supplied with the St Edward's Crown or the Scottish Royal Crown.

On the original Mark 1 and 2 Kiosks the crown was cast in the Crown panel.  Circa 1956 the crown was cast on a separate plate which slid into place on the Crown panel, which allowed any Crown to be installed when ordering.  The Royal Crown of Scotland was also introduced at that time, to be fitted to any kiosk installed in Scotland.

These can found on Drawing - 60908 (dated 1935).

St Edward's Crown - Used in England
Kiosk No. 6 Mark 2

Royal Crown of Scotland - Used in Scotland
Kiosk No. 6 Mark 2

Additional Pictures

Kiosk No. 6 with STD equipment Kiosk No. 6 with prepayment equipment


Kiosk No. 6 - Internal layout - Prepayment

Kiosk No. 6 - Internal layout - Postpayment - London STD


Kiosk No. 6 - Main components

Interior view showing a 1936 Jubilee layout
This is a CB installation and therefore has an Emergency press button (located in the lower, centre notice frame)
Bottom left is the lighting time switch, whilst bottom right is the incoming mains fuse box

An interesting Kiosk No. 6 at Crulivig with "Hebridean doors".
Due to the high winds in this area these style of doors were fitted as they would be held shut
by the wind, instead of the outwards opening large single door which could be held open by the wind.


1952 pattern with St Edwards Crown (left) and 1936 pattern with Tudor Crown (right) at Bembridge, IoW


Rural style at Rothley, GCR


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Last revised: July 14, 2023