Campaign to save a Royal Regiment of Fusiliers battalion
Hundreds of veterans marched in London in a bid to save the second battalion of the Royal Regiment of Fusiliers.
The battalion, to which murdered fusilier Lee Rigby belonged, is to be withdrawn as part of plans to reduce the Army by 20,000 over 10 years.
Former soldiers from Northumberland, Lancashire, London and Warwickshire delivered a petition to Downing Street.
The Ministry of Defence (MoD) said the cuts were planned to make the army more "adaptable to future challenges".
The plan was announced in July to reduce the regular army to 82,000 by 2020. In 2010, the regular army had 102,000 personnel.
Wearing distinctive red and white plumes in their berets, the ex-servicemen marched to a fife and drum band dressed in ceremonial animal skins after they left Downing Street for Parliament.
Colonel Ian Brazier, Chairman of The Fusiliers Association, led the protest, which included several former colonels of the regiment, families and widows.
They were were joined by around ten MPs, including John Baron (Basildon and Billericay), who is leading a cross-party drive for a re-evaluation of the government's defence cuts.
Organisers claimed the demonstration outside Parliament is only the second public military protest since the British Army was formed in 1707.
Col Brazier - who recently interrupted Defence Secretary Philip Hammond's speech at the Conservative Party Conference, calling him a "disgrace" - said: "It makes absolutely no sense for 2RRF to be disbanded.
"The Government has spoken about efficiencies and cost savings, but there is no explanation for this unfathomable decision, despite repeated formal requests under the Freedom of Information Act.
"So far, this has been a striking demonstration of poor management and leadership on the Government's part, to say nothing of the betrayal of the hundreds of men who have served in the Second Battalion."
Mr Baron, a former Captain in the regiment, said the cuts "will not deliver the cost savings envisaged", adding that replacing regular troops with reservists will be expensive and lead to "unacceptable manpower and capability gaps".
He added: "Let us hope this march and the House of Commons debate on defence reforms this Thursday will encourage a rethink."
The second battalion of the Royal Regiment of Fusiliers has five companies with 600 personnel. It is an infantry battalion of the regiment, which has served in conflicts since 1674.
An MoD spokeswoman said: "We have been clear that the regular army is becoming smaller and over a year ago we also announced changes to its structure so it is more reflective of the complex global situation.
"These changes were led by the army, who took account of a number of criteria to determine which infantry battalions would be withdrawn, to ensure the Army is more adaptable to future challenges."
Fusilier Lee Rigby, of Middleton, Greater Manchester, was killed in a street in Woolwich, south-east London in May,