Martin de Vine, founder and Squire of the Foxs Morris dancers, said: "David Cameron was having a coffee and we saw him and just asked if he would have a picture taken.  "We dance in the style of Border Morris, and we black our faces because farm labourers who were out of work in the winter months would go around begging, performing a dance in return for money.  "They blacked their faces with soot because it was illegal to beg and they didn't want to be recognised. It was a disguise, in the same way that the leader of the troupe wears a top hat and is called the squire to take the mickey out of the local squire.  "It's not racist and offence is never taken. People from other cultural backgrounds don't see it as that at all. We have had an Arab person dancing with us in the past - it's not seen as racist."  However, debate has raged for decades about the origin of the blacked-up faces, with some historians suggesting the "disguise" explanation is a myth that hides the true origin.  The term "Morris" is said to be derived from "moorish", after the Moors of Morocco, and in the early 20th century border morris dancing was often referred to as "n***** dancing".  Some social historians also believe Morris dancing to be a parody of African tribal dances.  Will Straw accused critics of being "ignorant" when he was accused of racism after posing with members of the Britannia Coconut dancing group in April.  The Britannia Coconut group, or "Nutters" as they are nicknamed, claimed at the time that blacking up was a pagan tradition to disguise the dancers from being recognised by evil spirits.  The Foxs Morris group was founded in 1999 by Mr de Vine, the head teacher of Cookley School in Cookley, Worcestershire. The name is a rough acronym of Friends of Cookley School. The term border morris refers to the English/Welsh border where the dancing originated.  Caroline Watsham, who was playing the musical saw at the Banbury Folk Festival, said: "He was very nice, he was just enjoying the day out as a normal dad spending time with his young daughter, and they all seemed to enjoy the Morris dancers. He wasn't here in any official capacity.  "I was out playing my saw and someone came and said have you seen Big Dave is here? I thought they were talking about some giant of the folk world but it turns out it was David Cameron. He was having a cup of coffee nearby and paid a visit."  The Prime Minister's official spokesman said of the photograph: "I don't see it as something on which any kind of comment is needed." He said the Prime Minister shared that view.
The Prime Minister was pictured over the weekend with a troupe of Morris   dancers at the festival in Oxfordshire