A group of MPs has signalled their opposition to atheist bus ads which claim, “There’s probably no God. Now stop worrying and enjoy your life.”

They are encouraging Christian groups to launch a counter advertising campaign using the slogan, “But what if there is?”

A number of cross-party MPs support two Commons motions attacking the “religiously offensive and morally unhelpful advertisements”.

One of the motions regrets the British Humanist Association’s backing for the campaign and calls on ministers to “seek to remove” the adverts.

The atheist ad is appearing on 600 buses in cities across England, Scotland and Wales.

It will appear on an additional 200 bendy buses in London for a month. Two large LCD screens bearing the atheist message have been placed in Oxford Street.

Quotes from well known atheists have been placed on 1,000 posters on London Underground trains.

The use of the cautious word “probably” in the atheist campaign is believed to be due to concerns that a categorical denial of God’s existence could break advertising rules.

A complaint has been made to the Advertising Standards Authority (ASA), sparking exaggerated headlines that the ASA will be forced to decide whether God exists.