The Driver and Vehicle Licensing Agency (DVLA) has withdrawn two numberplates from a prestigious auction which began yesterday for fear of causing widespread offence.
Red-faced officials ordered the registration 1 NLA to be removed because it could be doctored to read 'INLA' - the acronym for the outlawed Irish National Liberation Army that assassinated Tory MP Airey Neave with a car bomb in the House of Commons car park in 1979.
The sale would have contravened a long-standing ban on plates associated with terror groups and could have sparked outrage amongst the families of 113 people killed by the paramilitary group during its violent 35-year campaign.
The registration PAK 11N was also pulled out because it could be altered to read 'PAKI IN' which includes the derogatory term of abuse often directed at immigrants from the South Asian Islamic Republic.
It could also be seen as an inflammatory reference to a current row over a backlog of visa applications that has delayed the entry of thousands of Pakistani nationals coming to the UK - including a blind cricket team, a pipe band and rock musician Mekaal Hasan.
A senior DVLA executive said "human error" was to blame for the registrations slipping through the net.
1 NLA was due to go under the hammer with a reserve price of £3,200 on the second day (subs: Thursday 3 Dec) of the three-day sale of 1,500 numbers expected to raise a total of at least £1.9 million.
But previous experience suggests that the final bid would have been a lot higher and it would almost certainly have raised a five-figure sum - or possibly even six-figures - at the auction at Tankersley Manor, Barnsley, South Yorks.
PAK 11N had a reserve of £400 for its auction on Friday and had been passed for sale along with 1 NLA by a DVLA internal standards committee that considers the merits of each registration mark.
The embarrassing gaff comes just over a month after the DVLA was forced to axe two homophobic plates - F4 GOT and D1 KES - from its last auction following a complaint from gay rights charity Stonewall.
Its 'proprietary steering group' is meant to police the ban on potentially offensive number plates that could be doctored to spell out words related to terrorism, religion, sex or other provocative themes.
"Missing the potential significance of these particular marks was human error. They have been removed as a precaution in case they cause offence," said Damian Lawson, DVLA Personalised Registrations marketing manager.
"More attention is being paid by the steering group for future sales. Out of the thousands of marks we sell, one or two may slip through the net.
"Some people may see a registration as offensive. Some people may not. We have to be very, very careful now."
Three million personalised plates have been sold raising a reported £1.3 billion since 1989 when the cherished numbers scheme was first launched. Online and telephone sales now generate £4.5 million a month.
One hundred and twenty auctions have been held since the first at Christies in South Kensington, London, where 74 registrations went under the hammer including 1A for £160,000, 1 T (£56,000) and MUS 1C (£65,000).
The highest sum paid for a registration at auction is £352,411 for 1 D in March this year.
The Agency's list of proscribed combinations includes 054 MA which could be displayed to resemble the first name of Al Qaeda mastermind Osama Bin Laden (OSAMA), HE58 OLA (HEZBOLLAH) and BU58 OMB (BUS BOMB).
Plates beginning with JE and ending HAD are also banned as they could be interpreted as 'JIHAD' - the Arabic term for holy war.
The Agency has been accused of being a spoil sport for banning the sale of seemingly-innocent sequences like 59 ANK (SPANK), 59 ERM (SPERM), BO10 CKS and P10 NKA (PLONKER).
But the rules have allowed other risqué marks to be sold including N4 KED (NAKED), NUD 9E (NUDE) and 701 LET (TOILET).
The INLA gaff comes shortly after the republican paramilitary group announced (subs: Oct) that it is to give up its weapons and pursue purely peaceful politics.
It was formed in 1974 following an internal split within the IRA and the group is credited with the murder of 113 people including Neave, the Shadow Northern Ireland Secretary who died on 30 March 1979 and was one of the closest political allies of the then Prime Minister in waiting Margaret Thatcher.
A small number of members opposed to the 1998 ceasefire are thought to have defected to the Real IRA and Continuity IRA which continue to commit atrocities in Northern Ireland.
The 'PAKI' plate blunder comes as the Pakistan Army launches a major assault against Taliban and their Al Qaeda allies on the border with Afghanistan.
An estimated one million Pakistani Britons live in the UK - the second largest overseas Pakistani population - and the majority are Muslims.
Home Secretary Alan Johnson was forced to promise in October to clear a backlog of 5,000 visa applications and 9,000 appeals and cut the time it takes to process applications from two months to 15 days.
The DVLA came under criticism last year for seeming to encourage drivers to illegally doctor number plates to display words.
Sales literature now contains a warning for buyers not to "misrepresent" the appearance of plates and ensure they comply with the Road Vehicles (Display of Registration Marks) Regulations 2001 which specifies the typeface, size and spacing of letters and numbers.