More than 1800 officers and men from Scottish regiments are to be sent to Afghanistan to add punch to the frontline fighting strength of 16 Air Assault Brigade when it takes responsibility for Helmand province next month.

Soldiers from three of the Royal Regiment of Scotland's five regular infantry battalions and the tank and light reconnaissance squadrons of the Scots Dragoon Guards are to deploy over the next few weeks to prepare for a pivotal spring offensive against the Taliban.

An announcement of the composition of the 7800-strong force, first revealed by the Herald last October, was to have been made in Parliament yesterday, but had to be postponed when MPs ran out of time on other business.

The Argylls (now 5th battalion, RRS) - a specialised helicopter assault force - will be joined by the Royal Highland Fusiliers (2nd RRS) and by a reinforced armoured infantry company of 150 men from the Highlanders (4 RRS) for the Afghan mission.

The two infantry battalions are short of almost 200 soldiers and need to be brought up to strength by drafts from the other RRS regulars and from the Highland and Lowland Territorial battalions.