TONY Blair last night promised soldiers of the Black Watch they would be home for Christmas after their Iraq tour of duty.

His pledge came as ministers were preparing to make a formal announcement that the 650-strong battalion will move from the UK area of operations around Basra to the US sector.

Meanwhile, there was still no word on the fate of kidnapped aid chief Margaret Hassan, as her second day in captivity drew to a close.

The Cabinet is expected to discuss the deployment of troops this morning, after a report from a British reconnaissance team was delivered to Chief of the Defence Staff General Sir Michael Walker.

If ministers' discussions, and Sir Michael's recommendation, are straightforward, then Defence Secretary Geoff Hoon is expected to announce the move to MPs before a defence debate this afternoon.

Mr Blair insisted yesterday no decision had been taken but confirmed that the 650 men from the Black Watch would be those involved if the US request - to free up its forces for battles with insurgents - was agreed to.

Mr Blair declined to say where they would be operating if the deployment went ahead, although he repeated Mr Hoon's earlier assurances that it would not be Baghdad or Fallujah.

In the Commons, Tory leader Michael Howard urged Mr Blair to "be straight with parliament and the country".

The Prime Minister told him: "A decision has not been taken."

He added: "We are about to enter a period of increased activity in Iraq. This has nothing to do with the American elections. It has everything, however, to do with the Iraqi elections in January.

''We have to create the conditions in which fair elections under United Nations supervision can take place."

Mr Blair said the military request was being considered, adding: ''If we do it, the Black Watch will still be back home by Christmas at the end of their six-month tour of duty."

The Prime Minister also denied speculation that military chiefs had been unhappy about the American request.

Liberal Democrat leader Charles Kennedy said his party would oppose the proposed deployment because it was not at the request of British commanders.

Earlier in the day, Margaret Hassan's Iraqi husband made an emotional plea for her release, and both Mr Blair and Irish Premier Bertie Ahern said that every effort possible was being made to free her.

The government in Iraq condemned the kidnappers as "despicable".

Mrs Hassan, who was born in Dublin and has dual British-Iraqi nationality, was seized on her way to work in Baghdad on Tuesday after gunmen blocked her route and dragged the driver from the car.

Care International, who she works for, said yesterday it had halted its operations in Iraq following the abduction and said it was taking every possible step to secure Mrs Hassan's release.

Speaking on Al-Arabiya TV, Tahseen Ali Hassan, a retired economist, said: ''I would like to tell the kidnappers that we are in the holy month of Ramadan and my wife has been helping Iraq for 30 years and loved this country.

''In the name of humanity, Islam and brotherhood, I appeal to the kidnappers to free her because she has nothing to do with politics."