The Catholic Church’s bill for Pope Benedict’s visit to the UK has reportedly doubled from £7 million to £14 million.

The September visit has been opposed by gay and secular campaigners, who have accused the Pope of opposing gay rights, abortion rights, gender equality and the use of condoms to fight AIDS.

They estimate it will cost £20 million in total, with the church footing some of the bill while the rest is picked up by taxpayers.

According to a report in today’s Spectator, the church originally predicted its costs for the four-day trip would be £6.75 million but Catholic archbishops of England and Wales were told at a private meeting last week that costs had risen to nearer £14 million.

The magazine added that preparations for the visit were going “badly wrong” with major venues not yet booked and likelihood of the trip’s centerpiece, an open-air mass at Coventry airport, being cancelled and moved elsewhere to a smaller venue.

The last Papal visit to the UK, that of John-Paul in 1982, was funded by the church and left it deeply in debt.

Pope Benedict was invited to Britain by former Labour prime minister Gordon Brown, who is understood to have said the UK will not cover all the costs of the visit.

A spokesman for the Catholic Church told the Spectator: “The final programme is not confirmed yet.

“All venues are subject to confirmation — the final itinerary will be fixed in July. Progress is being made quickly.”

The National Secular Society said the government could not cut public services while bailing out the Catholic Church for the cost of the visit.

NSS president Terry Sanderson said: “The taxpayer is already committed to spending an unspecified amount of money – likely to run into tens of millions of pounds – for the state element of the visit, not to mention the considerable costs of security which are not being revealed.

“Under no circumstances must the public purse now be made to cover the church’s deficit, a deficit that has been incurred through arranging inflated events that they cannot afford to stage.”

He added: “We are not being told the truth about the real cost of this event. The taxpayer should not be put in the position of having to rescue the church from its own profligacy. This event is not necessary, hospitals, schools and social services are.”

When the event was first announced, the NSS gathered a petition of 28,000 names protesting at the state funding of the Pope’s visit.