Waitrose
Customers who have bought the affected chocolate bars can return them to Waitrose for a full refund Getty Images

Waitrose is to recall four varieties of its chocolate bars over fears they may be contaminated with pieces of plastic.

The affected own-brand products – which have a best-before date of July 2018 – include plain white chocolate, white chocolate with matcha tea and pistachio, milk chocolate with pistachio, almond and hazelnut, and milk chocolate with feuilletine and sea salt.

The Food Standards Agency urged customers who have bought the 85g chocolate bars to not eat them and return them to the store from where they were bought for a full refund.

Other Waitrose products are not known to be affected.

The upmarket retailer released a statement apologising to affected customers.

"We are recalling the above products, as there is the potential that a small number of bars may be contaminated with pieces of plastic," the statement said.

"Customers who have purchased any of the above products should not consume them, but return them to Waitrose for a full refund.

"We apologise for any inconvenience to our customers."

Customers who bought the affected chocolate bars can call Waitrose's customer care helpline on 0800 188884.