“I was absolutely gutted when I saw what had happened,” he said.
“I know the Banksy story but it doesn’t give people the right to do this. To see this is horrendous.
“I grabbed stuff from home and came down after I heard a cleaning guy on BBC Radio Berkshire, who explained what to do.
“I thought I would come down and have a go, but I’m hoping someone else will sort out the typewriter – I won’t be able to do that.”
Vandals have defaced the Banksy mural in Reading with red paint
The new graffiti appears to refer to the famous street artist King Robbo, who had a long-standing feud with Banksy.