Foreign Secretary William Hague described the Libyan rebels' fight for freedom as "inspiring" following a meeting with insurgent leaders in Benghazi.
Mr Hague made an unannounced visit to the rebel stronghold yesterday hours after the UK escalated its military operations with air strikes by combat helicopters.
After witnessing at first hand the results of months of brutal repression by forces loyal to Muammar Gaddafi, he wrote on microblogging site Twitter: "In Malta, returning from Benghazi. The work and hope of many Libyans for freedom is inspiring, as I've now seen for myself."
Among the places he visited with International Development Secretary Andrew Mitchell was a medical centre where they met some of those wounded in the conflict.
During the visit, Mr Mitchell announced a £182,216 package to help clear landmines which have already seriously injured hundreds since the uprising began in February.
Top of Mr Hague's agenda were discussions with the chairman of the interim National Transitional Council (NTC), Abdul Jalil, about his "political roadmap".
The Council is recognised by the UK as the legitimate post-Gaddafi government and has been given significant non-military assistance by the British Government.
Ministers stressed the importance of "developing plans for a competent, inclusive and transparent administration that includes clear civilian control of military and regional representation".
They also laid a wreath at Commonwealth War Graves, met with citizens in the city's Freedom Square and talked with leading civil society groups as well as humanitarian bodies.
Mr Hague said the principal reason for making the journey was "to show our support for the Libyan people and for the National Transitional Council, the legitimate representative of the Libyan people".
He added: "We are here together as part of a coordinated and strategic approach to Libya - ensuring that our military, diplomatic and development actions are aligned."
Renewing calls on Gaddafi to go, he said the dictator was "isolated internationally and domestically" and "continues to abuse human rights without mercy or compunction".
In May, Prime Minister David Cameron invited Mr Jalil to establish a formal office in London following talks in Downing Street - and boosted Britain's presence in Benghazi.
A joint team of specialists from the Foreign Office and Ministry of Defence is helping build "command and control capacity" including communications, media and support for the police.
More radios were sent this week and uniforms and bullet proof vests are due to be delivered soon. A UK-led International Stabilisation Response Team is also in place.
Their ministers' arrival was announced just hours after two Army Air Squadron Apaches came under fire as they completed the first helicopter mission of the Nato-led conflict.
The Ministry of Defence said they destroyed a radar installation and a military checkpoint near Brega overnight - deploying Hellfire missiles and 30mm cannon.
Both returned safely to the Royal Navy helicopter carrier HMS Ocean, which is stationed off the Libyan coast.
RAF ground attack aircraft also destroyed another military installation in the same area and successfully attacked two ammunition bunkers at the large Waddan depot in central Libya.
Intelligence on the whereabouts of Gaddafi's forces was "improving in a very satisfactory manner, despite their efforts to conceal themselves", Major General Nick Pope, the Chief of the Defence Staff's Strategic Communications Officer, said.
The use of Apaches has alarmed some MPs about the prospect of an escalation in the conflict and the danger to British lives.
Labour MP Graham Allen criticised the "mission creep" and called for a fresh Commons debate and vote.
"The way out of this mess is not to keep cranking up the military hardware and having so-called 'implied tasks' added on against the express view of the House of Commons; what we need to do is figure out how we can get a political solution that will last for several generations in Libya rather than this adventure which has no prospect of coming to a close," he said.
On Wednesday, Nato announced it was extending its mission in Libya for a further 90 days.
The latest aid cash boost will go to the Mines Action Group to enable its experts to identify areas contaminated with the explosive devices and clear them.
Reports suggest that as many as one in 10 of 4,000 injured people treated by medics in the port city of Misrata have required amputations as a result of stepping on mines.
The UK contribution will help ensure the safety of 200,000 people, including 82,500 children, in Misrata, Benghazi and other affected areas, officials said.
The Apaches were back in action again last night - using Hellfire missiles to destroy a multiple rocket launch system on the Libyan coast near Brega.
RAF Tornados also joined other Nato aircraft in what the MoD called a "major strike" on a large surface-to-air missile depot in the capital Tripoli.
"Since the start of military operations to enforce UNSCR 1973, Royal Navy, Royal Air Force and Army Air Corps forces have successfully attacked over 410 regime targets involved in Colonel Gaddafi's persecution of the civilian populace," Maj Gen Pope said.Reuse content