Manchester United will be 'homeless' if they want to expand Old Trafford to a capacity of 90,000.

According the managing director Richard Arnold, any attempts to add an extra tier to the Sir Bobby Charlton stand would be a massive engineering challenge.

The work that would be required to expand from the current capacity of 76,000 will have to take place over a number of seasons, if plans are given the green light.

Manchester United would have to be 'homeless' if they are to expand Old Trafford

Arnold told South China Morning Post: 'We haven't left the easiest stand until last. The Sir Bobby Charlton Stand is the last unexpanded stand.

'There's not much space on either side of the stand meaning that it's a very complex engineering challenge.

'It would be a multi-season challenge and it isn't certain there's a way of doing it which doesn't render us homeless.'

Managing director Richard Arnold said there is a huge engineering challenge to expanding

This season Tottenham have played their home games at Wembley while their new ground in being constructed.

And Arnold lamented the fact that United don't have the option of moving to the national stadium temporarily, with a shortage of options in Manchester.

'We have the biggest fanbase in the country and we're not in London, where we could use Wembley.

'So that's not a light challenge and we don't want to give up the home advantage we have here,' he added.