The ageing Russian aircraft carrier that sailed through the English Channel escorted by the Royal Navy has been plagued by years of technical problems and is accompanied everywhere by a tug in case it breaks down.

The plumbing is so bad on the 55,000 ton Admiral Kuznetsov that many of its toilets cannot be used, while it has had repeated problems with its power and a string of accidents, naval experts said.

The Soviet-era warship is leading a flotilla of eight naval vessels to the eastern Mediterranean, where its aircraft are expected to join a renewed assault on the rebel-held city of Aleppo.