The 50th Anniversary of the release of the Routemaster (at the 1954 Commercial Motor Show) was held at Finsbury Park, London on the 24th & 25th of July 2004. Brian Burgess has kindly sent in a selection of his images with accompanying text that I'm pleased to present below:
(Read Brian's Ode to a Routemaster here)

          Routemaster's 50^th anniversary rally at Finsbury Park in 2004.
 Pictures & Text by Brian Burgess.

Left: The commemorative poster for the event showing RM1 as it was originally designed.

Right: The layout of Finsbury Park showing the event locations and facilities.

Above Centre: Authorised Vehicle Pass

RM1 had a very different front-end when built (flatter and with the engine cover extending high over the wheel-arch).  This was rapidly changed due to alterations to the front running unit and, in particular, to give the driver more kerb visibility. RM1 didn't receive its new front end until 1964.

Here RM2, SLT 57 is having her original front reinstated at the LT Museum Depot at Acton having lost it in 1964 when the standard RM front was fitted. (Note: not pictured at the 50th but placed here for completeness).

RM3 (originally RML3) arriving at Finsbury Park in for the RM’s 50^th anniversary with its ‘original’ 1956 front end under wraps.

RM3 was a prototype built by MCW with Leyland running units; hence the original RML3 designation. Given the registration SLT 58, it was taken into London Transport in 1957.

And here is RM3 sporting its original 1956 front-end.  The "L" from RML3 was dropped in 1961 to avoid confusion with the "L" then being used to identify the lengthened RMs. She was retired in 1972.

CRL4 (renumbered to RMC4 in August 1961) seen arriving at RM's 50^th anniversary.

RM5 (VLT5) arrived at Finsbury Park for the RM’s 50^th anniversary rally.

RM6 (VLT6) at RM's 50^th anniversary rally. RMs 5,6 & 7 were the designation for some prototype test rigs. Whilst the rigs gained proper bodies the RM designations were reallocated. 

RM7 (VLT7) appeared at RM's 50^th anniversary after not being seen in public for some 20 years.

SRM3 renumbered from RM1650 for Queen’s Silver Jubilee in 1977.

RML 2760, as befits her honour of being the last RM built, is in excellent condition and followed closely by the bus that should have replaced her on London's streets: FRM1 (agreed Ed.).

KGJ 603D (Body # B54295) was built in November 1966 for BEA services from Victoria to Heathrow as BEA3. Sold to LT 6/79 and renumbered RMA29. The stairs were removed and she was used as trainer at Peckham Garage (PM ) being sold  in 1988, nearly scrapped but then rebuilt with stairs, an extra bay, and renumbered RME1.

A restoration to original spec by RM 1001. As she was a few buses up from RM 912 in the line up she would have proved a worthy target to aim for.

RMF 1254 was built in 1962 as a demonstrator for a front entrance market entry attempt. Used by LT on the BEA Heathrow shuttle before being bought by Northern General to go with their 50 front entrance versions of this vehicle.

I could not do justice to the complicated story of RM 912 so here is a link to the owners site! Suffice to say she was scrapped and cannibalised in 1998 and has survived as a bit of a Frankenstein version of a RM with many parts from different buses! Note that the short lived offside rear number panel has been replaced, so hopefully she will end up a superb original condition RM (http://ronsroutemasters.webs.com/rm912.htm).

RM24 in pristine condition. She entered service in June 1959 at Willesden Garage (AC).

RMC1485 dates from October 1962 and started her life at Windsor Garage (WR) on Green Line services and would have been gleaming in LT Lincoln Green.

RM470 entered Finsbury Park after a small jog over from Dusseldorf where she now lives. There is an image of her old number plate (WLT 470) now adorning a training bus in Camberwell Garage (Q) in the Routes & Routemasters page. She can also be found here in the Routemasters Around the World page.

RM1101 advertising her current home. A veteran from 1962 she was sold out of service in 1994.

Another RM in stunningly original condition. I have a 1/24th scale die cast model of RM254 on my mantelpiece!

RMC1476 dates from October 1962 but went to Guildford Garage (GF) for Green Line service. She is pictured here in NBC Leaf Green livery that my photograph, in the fully bright sunshine, is bleaching and has sadly somewhat distorted the effect of the livery. This livery was carried by some of the ex Lincoln Green LT Country Bus fleet that moved from LT into the London Country Bus subsidiary of the NBC (National Bus Company) on the 1st January 1970.

Alongside is RMC1477 which also started at Guildford Garage (GF) in 1962 with her sister parked next door. RMC1477 is shown here in the ‘as delivered’ LT Lincoln Green livery.  Again the strong sunshine did not do this colour justice. She carries the first livery applied to Green Line coaches with the metal roundel centred on the upper sides.

RCL2229 showing the later Green Line livery which can be compared with both RMC1476 & 7 in the previous photographs. Not as nice! GREEN LINE in capitals and no metal roundel....yuk.

A sneak round the back coinciding with a bit of cloud cover reveals the difference between Lincoln and Leaf Green a bit better. Note the stylish GREEN LINE logo (With LONDON TRANSPORT underneath, in a box!)

Like the RM with its family of variants (RM, RML, RMC, RCL, RMA and RMF) it’s predecessor on the streets of London, the RT, had a family (RT, RTL and RTW) although slightly smaller in variants, the total numbers far exceeded the RMs. There were 4,825 RTs, 1,631 RTLs and 500 RTWs a grand class total of 6,956. RT2177 is an excellent representation of the RT variant, she worked in London from 1949 until 1977.

One of the many buses that day which graced the streets of London before the RM. STL2377 dates from 1937.

RTL139 entered service in 1949 and was withdrawn in 1967 and would have rubbed shoulders with members of the RM family no doubt in many garages.

Likewise, RF139 would have shared garage space with the RM family as she served in London from 1952 to 1976.

The first 8’ wide buses allowed in central London were the RTWs. Like the RTL, this bus was on a Leyland chassis and so carried their distinctive radiator shape, as opposed the AEC radiator seen on the RT. RTW29 entered London service in 1949 and came out of service in 1969. Withdrawn RTWs were used by LT as trainers for the new RMs which were of course 8’ wide.

RMs as far as the eye can see.

Another view this time down the line up. 2 RMs in LT Lincoln Green and one in NBC Leaf Green stick out. LXU 397 is RM1397 whose original number plate would have been 397 CLT.