Britain pledged to step up attacks on Colonel Muammar Gaddafi’s forces on Saturday as Apache attack helicopters joined the battle for the first time.
Two £40 million Apaches, launched from a ship off the Libyan coast, pounded ground defences in a devastating show of strength.
They fired laser-guided Hellfire missiles to destroy a radar installation to the west of the oil port of Braga, then blew up an anti-aircraft gun before their two-man crews returned safely, despite coming under enemy fire from AK47s.
Meanwhile, in a carefully timed move, William Hague, the Foreign Secretary, declared rebel leaders to be the “legitimate representatives of the Libyan people” as he and Andrew Mitchell, the International Development Secretary, became the first British ministers to visit the country since the military operation began in March.
It also emerged that Britain is likely to send a fifth Army Air Corps Apache to help the campaign, to join the four already there.
The Apache attack, launched 15 miles off the coast from the Royal Navy’s biggest warship, the amphibious assault ship HMS Ocean, was the first time in the 10-week campaign that allied helicopters had combined with fast jets.
Both Apaches were flown by veterans of the Afghanistan campaign. They fired six missiles at the radar base and then destroyed the gun emplacement using their powerful 30mm underslung cannon, in an operation lasting just 90 minutes.
Behind them, Nato fixed wing bombers attacked separate targets in a carefully synchronised attack, while French Gazelle helicopters launched from the carrier La Tonnerre sought out a further set of targets.
During the assault early yesterday, 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.
Liam Fox, the Defence Secretary, denied the use of Apaches had been taken because the original military campaign was not working well enough.
“It’s not plan B at all,” he said, speaking at a security forum in Singapore. “The use of the attack helicopters is a logical extension of we have already been doing. We already have fast jets in action, this gives us a chance to target new targets in a way we weren’t able to do.”
Mr Hague and Mr Mitchell touched down by helicopter in the rebel-controlled stronghold of Benghazi, where they met rebel leaders and key members of Libya’s National Transitional Council (NTC) including its head, Mustafa Abdul Jalil.
The Foreign Secretary praised the NTC and repeated the demand of Britain and its western allies for Col Gaddafi to be removed.
He said: “We are here today for one principal reason – to show our support for the Libyan people and for the NTC, the legitimate representative of the Libyan people.
“Britain remains a strong and true friend of Libya. We could not and did not turn a blind eye when Gaddafi turned his forces against innocent civilians. For as long as Gaddafi continues to abuse his people, we will continue and intensify our efforts to stop him.
“The UK is committed to this task. Col Gaddafi is isolated internationally and domestically. He has lost all legitimacy, continues to abuse human rights without mercy or compunction. He must go.
“We are here together as part of a coordinated and strategic approach to Libya – ensuring that our military, diplomatic and development actions are aligned.”
The UK already has a joint team from the Foreign Office and Ministry of Defence in Benghazi, advising the NTC on its long-term plans. Communications equipment, bullet-proof vests and uniforms have also been provided to the civilian police authorities, while the NTC has been invited to set up a formal office in London.
The rebel-led campaign against government forces has been bogged down in recent weeks amid fears of a stalemate. Last Wednesday, Nato extended its Libyan mission by 90 days.
The decision to send four Apaches to Libya was taken by David Cameron just over a week ago, as he talked of the need to “ratchet up” the campaign. The low-flying capacity of the attack helicopters - dubbed “mosquitos” by the Taliban in Afghanistan - makes them more accurate in attack, leaving less chance of civilian casualties than in missions flown by Tornado and Typhoon aircraft.
However, the decision also brings a greater threat to crews, as the Apaches, with a maximum speed of about 200mph, could be more easily targeted by Libyan government forces loyal to Col Gaddafi, which still have access to thousands of surface-to-air missiles.
The commanding officer of 4 Regiment Army Air Corps, Lt Col Jason Etherington, said: “This is an escalation in support of the civilians whom Gaddafi is persecuting. We will be given targets that perhaps fast jets cannot target because of the risk of collateral damage.”
Graham Allen, the Labour MP, claimed the introduction of Apaches was “mission creep” and said there needed to be a fresh debate in the House of Commons on Libya.