The Womble police in the form of songwriter Mike Batt was spotted sneaking into a children's sing-along on Sunday after publicly accusing organisers of breaching costume copyright.

Mr Batt ducked into the Wimbledon BookFest event hosted by fellow writer and musician Julian Butler on Sunday afternoon.

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The sing-along session was billed as a festival favourite suitable for children of all ages.

Mr Batt, who famously wrote theme songs including Remember You're a Womble and The Wombling Song, accused BookFest organisers of breaching copyright and 'passing off' the costumes as their own.

A series of tweets at the weekend attacked BookFest organisers and accused them of breaching copyright and 'passing off' the costume as genuine, saying it was not legally licensed to be used.

Festival director Fiona Razvi confirmed Mr Batt had been at the event but thought he was there to see the show. She did not wish to comment further.

On Saturday, he said: "Anyone off to see Wombles at Wimbledon Bookfest tomorrow? That Womble isn't legally licensed! Anyone know about it?"

A reply from another singer / songwriter David Doll suggested the event, which is held every year, should have been billed as a tribute.

Mr Batt said: "I'm sure they mean well, but it is a breach of ©, and "passing off". Go directly to jail, do not pass go, do not collec £200!"

With a touch of humour, Mr Batt said: "Wimbledon bookfest #THeWombles Bay Of Pigs stand-off style crisis averted. I am going down at 10am tomorrow to watch, discuss and join in."

He was spotted at the event where BookFest chairman Tony Kane said he criticised the costume and asked where it had come from.

Mr Batt is said to have made a hasty exit a short time later, refusing to be photographed by festival photographer John Stone.

When asked for a photo, Mr Batt is alleged to have said no and 'it would not be very political', before leaving the tent on Wimbledon Common, the home of the Wombles.

The loveable characters created by local resident Elisabeth Beresford MBE, who died in 2010, became world famous for their litter loving ways. Their attitude to recycling encouraged scores of children to re-think their everyday rubbish.

Mr Batt's songs and The Wombles pop group, which saw him dress up in the costumes to take to the stage, shot up the charts. Remember You're a Womble was released in 1974.

Tickets are still available for the second Wombles Storytelling and Sing-along event on Sunday, October 11. Visit www.wimbledonbookfest.org for information and tickets.