While the National Gallery in London now allows visitors to take photographs of its famous paintings using mobile devices, Manchester United football fans have been banned from taking an impromptu picture of their star player using an iPad.

The famed club will show the red card to anyone carrying such computer tablets – banning them from the terraces at Old Trafford (pictured above), citing safety and security.

As football fans look forward to the new Premier League season, Manchester United has outlawed ‘large electronic devices including laptops and tablets’ on home matchdays.

On its website, the club apologises for any inconvenience caused, explaining that ‘in line with UK airports, we are reacting to the latest security intelligence’.

It adds: ‘These actions are designed to ensure the continued safety and security of all spectators’.

Any item larger than 150x100mm faces the ban.

However, mobile phones and ‘small lens cameras’ will be allowed, provided they meet the size criteria.

The club says it would be ‘impractical’ to ask spectators to ‘power-up’ their devices before entering the stadium, like the rules brought in by UK airports earlier this summer.

The news comes as the National Gallery in London relaxes its rules on photography.

Visitors have been told they can now use smartphones or tablets to explore the gallery’s 2,300 paintings, and share their experiences via social media as part of a new free-to-use Wi-Fi service.

A National Gallery spokeswoman today told AP that pictures can only be taken for personal, non-commercial, use.

Flash photography will not be allowed.

Staff will be allowed to use their discretion if the act of taking pictures prevents others from viewing the gallery’s paintings, which date from the 13th century.

Manchester United’s rules