A MAN has been arrested on suspicion of conspiring to murder PC Yvonne Fletcher, who was shot dead outside the Libyan embassy in London 31 years ago.

The Libyan suspect, in his 50s, was held at a location in south east England in what police described as ''the first significant arrest'' of the investigation into the 25-year-old officer's killing in 1984.

Detectives have also arrested a man and a woman on suspicion of money laundering.

PC Fletcher, from Semley near Shaftesbury, was gunned down when Libyan officials opened fire on a demonstration outside the building that she was policing.

In 2011, the Daily Echo reported that the then-new Libyan government said that the man suspected of gunning her down, Matouk Mohamed Matouk, would be tried if caught.

At the time, Matouk was one of three suspects believed to still be alive and on the run.

Now, he is thought to be the last known named suspect still alive.

He later became one of the most senior figures in Colonel Gaddafi’s regime, but he disappeared when Gaddafi’s rule collapsed.

It is not yet known whether Matouk is one of those that has been arrested.