Michael Shields had been due to fly back to the UK on 29 May

Bulgarian prosecutors on Monday charged Michael Shields with attempted murder, and Anthony Wilson with hooligan behaviour and drugs possession.

The pair, both 18 and from Liverpool, spent several days in Bulgaria after watching the English club's European Cup Final triumph in Turkey last month.

The alleged victim, a 25-year-old man, was said to have been hit by a stone.

He is believed to have suffered head injuries.

This is worse than a nightmare for our family Michael Shields senior

If convicted, they could face up to 20 years in prison.

A third Briton also implicated in the incident, Bradley Thompson, 19, from Liverpool, has received a suspended six-month sentence.

Mr Shields and Mr Wilson were among a group of fans who had been due to fly home on 29 May.

But that morning Bulgarian police entered their hotel and arrested four of them on suspicion of injuring a man a few hours earlier.

Court spokeswoman Elena Bangieva said on Monday that the charges were filed in the port city of Varna and a hearing was scheduled for 21 July.

Supporting his son

Earlier this month, Varna District Court ordered Mr Shields and Mr Wilson to be held in custody pending trial. So far they have been in prison for 29 days.

Mr Shields' father, also called Michael Shields, insisted his son was innocent.

The window cleaner, from Wavertree, has just returned from Bulgaria, where he has been supporting his son.

He said: "We haven't been officially informed of any charges so we do not know what is going on at the moment.

"Obviously we just want him out of there and back home where he belongs.

"He is a good lad and has never been in trouble with the law.

"This is worse than a nightmare for our family, but we'll do everything in our power to prove Michael's innocence."