Gianfranco Techegne in 1982 (R) and now

A mafia man convicted of killing an Italian policeman, and who has been on the run for 30 years, has been arrested in London - directly opposite Scotland Yard.

Italian authorities have been trying to detain Gianfranco Techegne since 1982 when he is suspected of murdering a police officer in Naples, reports Sky News.

The Metropolitan Police said he was caught on Tuesday after being identified in a post office across the road from their headquarters.

"Acting on intelligence, detectives from the MPS Extradition Unit spotted Gianfranco Techegne, casually queuing up in the post office in Broadway, SW1," a police spokesman said.

Techegne has a daughter in London with a Bolivian woman he married while on the run, authorities in Naples said.

Italian prosecutors claim Techegne shot police officer Vincenzo Truocchio who attempted to tackle him and two accomplices as they carried out a raid in the centre of the Italian city.

The policeman died in hospital from his injuries nine days later and was posthumously awarded a bravery award.

Massimo Sacco, of Naples Police, said: "Techegne had been a prime target of ours for years because he had murdered a fellow officer and his arrest has been greeted with much satisfaction by friends and former workmates of his victim.

"We were able to track him down thanks to advances in technology and the fact that he made mistakes but as the investigation is still on-going it would not be right to disclose any further details at this moment."

Italian police said they are investigating the possibility that he had been helped by other suspected mafia members, thought to be based in London working in Italian restaurants and the fashion trade.

Italian courts have sentenced Techegne to 15 years and four months in prison in his absence and say he will now be extradited to serve his sentence.

Two accomplices caught at the time of the Naples shooting have already been freed after serving 25 years and 16 years respectively.