Boots has apologised for the language it used after Labour MPs wrote an open letter to its chief pharmacist to express “deep concern” about the company’s refusal to reduce the cost of emergency contraception amid calls for a boycott.

Jess Phillips said the firm was "infantilising women" as the Women's Parliamentary Labour Party backed a campaign by the British Pregnancy Advisory Service (BPAS), a leading provider of abortion care.

Tesco and Superdrug have already agreed to halve the price of the morning-after pill as a result of the BPAS campaign but Boots has so far resisted the calls.

On Thursday, Boots said it would not lower the cost of its product, saying that the high street chemist did not want to be accused of “incentivising inappropriate use”.

But on Friday evening a statement from the company said it "apologised" for its "poor choice of words".

The pharmacy chain charges £26.75 for a generic version of the pill, double the charge levied by both Tesco and Superdrug.

Campaigning charity BPAS has been pressuring shops to reduce the price of the pill, which is available for as little as £5.50 in France.

In a letter to Boots' chief pharmacist Marc Donovan, Clare Murphy, the director of external affairs at BPAS, said: "Generic versions of Levonelle can now be bought by pharmacies for as little as £1.50, but these savings are not being passed onto women" and asked Boots if it would reduce its prices.