British forces on Sunday took part in a "co-ordinated strike against Libyan air defence systems", the country's military said.
"I can confirm that British armed forces have participated in another co-ordinated strike against Libyan air defence systems," Chief of Defence Staff's Strategic Communications Officer Major General John Lorimer said in a defence ministry (MoD) statement.
"For a second time, the UK has launched guided Tomahawk Land Attack Missiles (TLAM) from a Trafalgar Class submarine in the Mediterranean as part of a coordinated coalition plan to enforce the (UN) resolution," Lorimer added.
The attacks marked the second day of Britain's participation in an operation to enforce a UN-sanctioned no-fly zone over the north-African nation.
Britain said earlier Sunday its initial overnight air and sea strikes had been "very successful" and stressed it was doing everything it could to avoid civilian casualties.
Sunday's attack came hours after Tornado fighter jets, similar to those used to fire Storm Shadow cruise missiles at Libyan targets on Saturday, were seen taking off from Marham air base in east England.
The Trafalgar Class submarine was also involved in the first wave of attacks with US forces which saw more than 110 Tomahawk missiles fired at some 20 air defence targets.
