Lady Thatcher's former spokesman has accused the McCartney sisters of "monumental hypocrisy" over their decision not to share an awards platform with the former British prime minister.
Sir Bernard Ingham questioned how Claire and Catherine McCartney had arrived at their decision not to stand alongside Lady Thatcher at a Woman of the Year ceremony in London's Guildhall.
They had said in a statement they could not take part because of the "injustices inflicted" on Ireland by the Thatcher governments.
Sir Bernard accused the family of double standards by demanding justice for their murdered brother while refusing to stand with Lady Thatcher who was also an IRA target when the Conservative conference in Brighton was bombed in 1984.
"Mrs Thatcher has a wonderful capacity to smoke people out.
"I think it is very interesting that the McCartney sisters protested at IRA thugs killing their brother. Where were the protests when IRA thugs were killing thousands of people and were trying to blow up Mrs Thatcher?" Sir Bernard asked.
He added: "It is a useful opportunity to draw attention to their campaign, but it does not strike me as having anything to do with justice."
However, one-time Tory chairman Norman, now Lord, Tebbit sympathised with the McCartney sisters.
Lord Tebbit said: "I do understand their position and I wouldn't want to criticise them. They've got troubles enough with Sinn Féin/IRA. It would enable Sinn Féin/IRA to justify their treatment of the McCartney family if they were to share a platform with Lady Thatcher."
One of the sisters told BBC Radio Ulster yesterday that they made an immediate decision not to take part in the ceremony on hearing of Lady Thatcher's participation shortly before it was due to begin.
Catherine McCartney said: "Our campaign is one of justice and our main focus is our brother Robert and the injustice that happened to him and to our family since January.
"But in the same way, we cannot ignore other injustices that have been carried out and we felt it wasn't possible to share a platform with someone we would certainly identify with carrying out injustices in Ireland against our own people."