A world authority on pain is flying into the UK to address MPs and peers in Westminster over concerns that they received inaccurate information on fetal pain when they were considering a possible reduction in the time limit on abortion.

Professor KJS Anand, from the University of Arkansas for Medical Sciences in Little Rock, Arkansas, believes that the Royal College of Obstetrics and Gynecology (RCOG) failed to present all the necessary scientific evidence to the House of Commons Science and Technology Committee last October.

The Human Fertilisation and Embryology Bill is still passing through Parliament and could see amendments to the 1967 Abortion Act.

Anand is to address MPs and peers at a special meeting on Monday night to ensure that they have all the scientific facts before making any decision to change the law.

Professor Anand, speaking from Bern in Switzerland where he is currently lecturing, said: "Members of the Lords and Commons are relying upon incomplete evidence given to the Commons Select Committee as the basis of their judgment on this issue."

He accused the RCOG of reporting only studies by researchers who share their official position "whilst ignoring research published by other leading researchers with contrary views". This was "at the very least misleading", he said.

"I believe the RCOG deliberately withheld relevant and scholarly research on this issue," said Professor Anand.

"My evidence will at least give them food for thought, and at best, may give them good reason to reconsider the time limit on abortions, but also to ensure better care for fetuses and neonates across the UK."

Professor Anand, who is not a member of any pro-life or pro-choice group, will be addressing politicians at the House of Commons event co-ordinated by Nadine Dorries MP.

Dorries was a member of the Science and Technology Committee and last year co-authored a minority report, which called for the scientific evidence to be given greater consideration.