Noel Barron was with his three-year-old grandson between Swiss Cottage and The Spa when he came across the first base, half-buried in the sand.
He picked it up, fearing his grandson or someone else would be hurt if they fell on it – and then saw another one.
“I found two or three, then a few more, than a few more,” said the 73-year-old retired primary school teacher.
Eventually, he had collected 43 and when he returned to the beach two days later, he found even more, collecting 60 in total.
“Some were standing vertically in the sand like sharp, rusty blades,” said Mr Barron.
“If you’re going to use them, you should count 60 out and make sure you count 60 back in.
“I will have to keep checking as I wouldn’t want anyone to injure themselves on one of these things.”