Western leaders pledge to continue their campaign to overthrow Col Gaddafi for another three months, as attacks on the Libyan dictator's strongholds intensify. The extension commits RAF Marham's Tornado force beyond the date when the future of their Norfolk base will finally be announced.

Allied forces stepped up the tempo of their efforts to topple Col Gaddafi overnight, as Apache helicopters joined Tornado jets in attacks on Libyan forces.

Earlier, Britain welcomed Nato's decision to extend its mission in Libya for a further 90 days, which could see operations continue almost to the end of September.

Operations to enforce the no-fly zone and use air power to protect civilians were authorised for an initial 90 days - up to the end of June - when the military alliance took over command on March 31.

But with dictator Muammar Gaddafi still holding firm in the face of international military action, the allies agreed an extension.

That means Tornado squadrons are likely to still be involved in the conflict on July 19 - the date now being suggested by Whitehall for the announcement over whether the aircraft's main base will be in Norfolk or elsewhere.

Overnight British combat helicopters destroyed a radar installation and a military checkpoint during their first operation in Libya, despite coming under fire.

The Ministry of Defence said Army Air Squadron Apaches successfully completed their mission of hitting the targets near the Libyan town of Brega overnight.

Forces loyal to Gaddafi fired at the one of the choppers, but both returned safely to the Royal Navy helicopter carrier, HMS Ocean, stationed off the Libyan coast.

Major General Nick Pope, spokesman for the Chief of the Defence Staff, said: 'The mission was carefully co-ordinated with other allied air missions by Nato's air operations centre, based at Poggio in Italy, under Operation Unified Protector, and in particular was planned alongside an operation by French helicopters from the assault ship Tonnerre.

'Hellfire missiles and 30mm cannon were used to destroy the targets.'

He said RAF ground attack aircraft destroyed another military installation in the same area, and another RAF mission successfully attacked two ammunition bunkers at the large Waddan depot in central Libya.

The Attack Helicopters, Tornados and Typhoons hit their targets which had been 'carefully and rigorously selected'.

Earlier, the MoD said massive stocks of ammunition were destroyed in strikes by Tornado and Typhoon aircraft on armament bunkers.

Military spokesman Maj Gen John Lorimer said: 'RAF ground attack aircraft conducted successive strikes against one of Colonel Gaddafi's largest ammunition depots, located at Waddan.

'As Nato operations have taken their toll on stockpiles closer to the coast, the regime has become increasing dependent on Waddan for the ammunition to sustain its attacks on the civilian population.

'The Tornado and Typhoon strikes yesterday destroyed 10 ammunition bunkers and a military vehicle at the depot.'

Marham aircraft took part in some of the first strikes on Libyan forces, as the conflict began on March 19.

Crews flew 3,000-mile sorties from the their Norfolk base to Libya and back - the RAF's longest mission since the 1981 Falklands conflict.

Ministers and senior defence officials are deciding whether to make Marham or RAF Lossiemouth, in Scotland, the Tornado fleet's home.

Air bases are under review as part of a package of cuts designed to slash Britain's �46bn defence budget by 8pc.

Tornado numbers are set to be reduced from 120 to around half that number. Marham's XIII Sqn has been disbanded, along with Lossiemouth-based XIV Sqn.

In the defence review, the RAF will lose 5,000 personnel, the Navy 5,000 and the Army 7,000.

Other casualties include the Harrier jump jet, aircraft carrier HMS Ark Royal, the Nimrod spy plane, tanks and artillery.

Politicians and community groups united behind a Make it Marham campaign launched by the EDP last November. It climaxed in a 30,000-strong petition being delivered to Downing Street.

The base supports more than 5,000 jobs and brings �30m to Norfolk's economy.