The RAF is "entirely comfortable" with the success of bombing raids over Libya.
Tornado GR4 fast jets and a Royal Navy Trafalgar-class submarine were involved in striking "high value targets" in the capital Tripoli and other parts of Libya as the international community swung into action against Muammar Gaddafi.
Detailing British involvement in the coalition's efforts against Gaddafi's forces, Air Vice-Marshal Phil Osborn told a briefing in London: "We are entirely comfortable with the way last night's mission went in terms of success."
He would not confirm if the Libyan air force had been destroyed but said: "It's fair to say that there is a threat, we always have to be aware that there may remain a threat."
Tornados flew from RAF Marham as part of an eight-hour, 3,000 mile round mission, the longest since the Falklands conflict.
In a co-ordinated strike on Libyan air defences, US and UK vessels in the Mediterranean fired 112 Tomahawk missiles at more than 20 targets around the coastal cities of Tripoli and Misrata.
Earlier, around 20 French Mirage and Rafale jets fired on tanks and armoured vehicles being used by Col Gaddafi's forces near the rebel stronghold of Benghazi.
The allied strikes followed an emergency summit in Paris to agree military action to implement United Nations Security Council Resolution 1973, which authorises "all necessary measures" short of foreign occupation to protect civilians in Libya.
Prime Minister David Cameron said that Britain's military involvement as part of a broad international coalition was "necessary, legal and right", adding: "I believe we should all be confident that what we are doing is in a just cause and in our nation's interest."
Gaddafi responded by vowing to conduct a long war "with unlimited patience and deep faith". He said arms depots were being thrown open to arm the Libyan people to defend themselves against what state TV termed "the crusader enemy".