British low-cost airline easyJet has offered to fly Pope Benedict XVI to Britain for free, after a controversy erupted over the high cost of the pontiff's visit.

The airline seized on a row that emerged after the pope criticised British laws seen as friendly to gays, prompting critics to point out that the visit would reportedly cost British tax payers #20-million.

"We are confident that once he has tried easyJet, His Holiness will never look back," easyJet said in a statement.

The airline said it contacted the Vatican on Wednesday to extend the invitation and was waiting for a response.

Pope Benedict, who usually flies with Italian airline and easyJet rival Alitalia, confirmed on Monday plans to visit Britain later this year in what would be the first such trip in 28 years.

But he sparked controversy in a letter to the bishops of England and Wales, saying new British equal opportunities legislation "violates the natural law upon which the equality of all human beings is grounded."

Observers said the pontiff was referring to legislation that took effect on January 1, 2009 preventing adoption agencies ? including Catholic ones ? from discriminating against gay couples.