Manchester City have apologised to volunteers for blocking them from wearing Manchester United shirts.

The Premier League champions held a media call to promote their 'Walking Football' programme at their £200million City Football Academy (CFA) on Friday and raise awareness of the game designed for over 50s.

Stars including Pablo Zabaleta and David Silva took on club legends Mike Summerbee and Peter Barnes along with a number of volunteers in a pre-arranged kickabout in front of the press and without a red shirt in sight.

The Daily Mail says the absence of any United colours was by design and not by accident.

A memo sent to participants ahead of the event by the club's community arm lays down the sky blue law.

"Please note" it reads, "only participants registered for our sessions will be allowed access to CFA (no spectators), the surface is the same as the tennis centre and please do not wear any MUFC kit as you won't be allowed in".

It is understood the message was meant to be lighthearted but the tone was lost in translation.

However, the club have been moved to say sorry.