SENIOR army officers are heading for Benghazi to sharpen up the Libyan rebel movement, prompting immediate concerns that Britain is being dragged further into the messy stalemate with Colonel Gaddafi.

David Cameron faced accusations of “mission creep” after the Government announced that about a dozen Service personnel would soon arrive in the main rebel stronghold.

The officers will be led by a lieutenant commander and have been told that they can expect to be in the country for six months, providing support with communications and command structures but not offering training in the use of lethal force.

In a pointed comparison, Sir Menzies Campbell reminded the Prime Minister that Vietnam began with the deployment of military advisers. “We must proceed with care,” the former Liberal Democrat leader said.

The Labour MP David Winnick criticised the move, saying: “There is a danger of mission creep. This is a big escalation of Britain’s involvement.”

The deployment of British vessels and 600 Royal Marines for amphibious exercises off Cyprus within two weeks has fuelled speculation that Britain is increasing readiness for land operations in the region, although the Ministry of Defence insists that the planned exercise is unrelated to Libya.

In the besieged city of Misrata, the army initiative was welcomed. Nouri Abdulati, of the city’s governing Judicial Committee, said: “We want a protective force in Misrata right now.” He described an “urgent need” for better trained and armed NATO or UN forces on the ground to prevent Colonel Gaddafi’s forces from overwhelming the city. “When we originally said no to foreign intervention, Gaddafi wasn’t attacking us with war planes and Grad rockets. Now we want to see French and British and Libyan revolutionaries fighting side by side.”

Ismail Tabal, 70, one of hundreds of displaced people lining up at an aid distribution point for a food handout, said: “We would like to see them here before six o’clock tonight (Wednesday).”

The British group will be along the coast at Benghazi to help to professionalise the rebel army, overseen by the National Transitional Council. The rebels have been dismissed as a “ragtag” group by some officials. William Hague, the Foreign Secretary, said that the army officers would “advise the NTC on how to improve their military organisational structures, communications and logistics, including how best to distribute humanitarian aid and deliver medical assistance.”

But there were demands for the recall of Parliament amid claims from some MPs that the allies were breaching the UN resolution. Sir Menzies said the move was an indication that an air offensive run by NATO committee was not enough to defeat Colonel Gaddafi.

Sir Malcolm Rifkind welcomed the deployment, however, suggesting that yet more troops might be needed.

“A decision will be needed both by Britain and the international community in the very near future as to whether to make a further step-change to ensure the defence of towns like Misrata,” the former Foreign Secretary said.

The Foreign Office denied claims of mission creep or breach of the UN Security Council Resolution 1973. A diplomatic source said: “They will not be there to help the rebels kill Gaddafi’s people. This is not an invading army.”

The French are also expected to send military personnel, bound by the same rules that prevent combat training.

At least one nation, Qatar, has indicated its willingness to arm the rebels, and Britain is likely to work closely with the Emirate in boosting them.

The military officials will form part of a bigger effort in Benghazi led by Christopher Prentice, the Foreign Office official on the ground.

Libya’s rebel president, Mustafa Abdel Jalil, put the death toll in the war at 10,000, with 50,000 to 55,000 people wounded. “Gaddafi will never give up power except by force,” he said.