A dog walker playing fetch on a beach reached for a pebble to throw to her pet - only to find she had picked up a Second World War grenade.

After picking up the dangerous explosive, Clair Watson, 41, called over to another walker and he phoned his son - who just happens to be an Army explosives expert.

He set up a cordon - averting a potentially deadly game of fetch - and called in a bomb disposal team to the beach at Dovercourt, near Harwich, Essex, on Monday.

Mrs Watson and her dog Bonnie found the fifth grenade in as many weeks on the beach, prompting the police to issue a warning to walkers.

Speaking of the heart-stopping moment, Mrs Watson said: 'I was going to throw it for the dog.

'It wasn't until I picked it up that I thought that is a weird looking stone.

'It didn't look like a hand grenade at all at first, but then I looked it.

'I said to my husband: "What the hell is that?". He said it looked like a hand grenade.'

A bomb disposal squad, police officers and the coastguard rushed to the beach and safely removed the explosive.

Inspector Paul Butcher, of Essex Police, said the grenades might have been in a crate that ended up in the sea during WWII.

He said: 'That crate might be breaking up or has been disturbed by dredging and has resulted in these devices being washed ashore along the same stretch of beach.

'We are asking people to be vigilant if visiting this beach and to dial 999 if they find any of these devices.

'Some of them have been covered in barnacles but the one yesterday looked almost as new despite being in the sea, possibly for many years.

'Anyone who finds a grenade should not touch it or move it but should call police immediately.'

Councillors are also considering a metal detector 'sweep' of the beach to search for any more explosive devices that could be hidden among the pebbles.