Supporters have been warned of the delay in a letter from United which has been sent out with match tickets.

The club have also passed on more specific information warning of the dangers of travelling independently to the stadium.

They have advised that supporters of other English teams have experienced major safety problems due to the violent behaviour of the local 'ultras'.

According to the letter, of particular danger are the metro trains to the Piazza Flaminio, the Ponte Nenni bridge and also the Campo de Fiori.