Park visitors said the man was seen in the Lakeside Cafe before a woman accompanying him realised he was missing. 

A police cordon remains at the scene, which is close to the cafe, although all paths have re-opened to the public. 

A woman who did not wish to be named said:-

"I was sitting in the cafe having a coffee and a lady was with the man.  She went up to order and I then saw her at the table looking for him.  She spoke to some other people and then she went outside to make phone calls.  The police turned up after that." 

A member of staff at the Lakeside Cafe added:-

"The man and his family are regular customers.  He's elderly.  It's very sad"