Mr McNamara said it was important that clarification should be given, either through the channels by which the Government had been in touch with republicans in the past or through the SDLP leader, John Hume. But he warned that such contact should not become extended negotiations.
John Major has taken the stance that no clarification of the Downing Street declaration is necessary, characterising the Sinn Fein calls as 'an increasingly desperate attempt to avoid facing up to the clear choice that confronts them'.
But pressure has increased on the Government as both Dublin and John Hume have made it clear they approve of clarifying policy. Dick Spring, the Irish foreign minister, indicated he would expect Mr Hume to meet Gerry Adams, Sinn Fein president, while Mr Hume said the Government should explain matters in the cause of peace.
Mr Adams yesterday tried to step up the pressure on the Government - and thereby relieve some of the burden on his own party - by announcing that he intended to write directly to Mr Major in the next few days asking him to clarify aspects of the declaration. The Sinn Fein president declared: 'Sinn Fein is totally committed to a meaningful peace process.
'It is in this context that we are examining and evaluating the declaration and the statements from both governments. If John Major is serious he should take the appropriate steps to advance this.'
The Sinn Fein tactic of calling for clarification of the document appears to be bearing fruit in that a number of important political sources have now signalled that they regard this request as a reasonable one.
Most observers agree that the declaration contains unclear passages. For example, Sir David Goodall, a retired British diplomat who helped write the 1985 Anglo- Irish agreement, has written of its 'ominous ambiguities'. Writing in the religious periodical the Tablet, Sir David complimented British and Irish officials 'who, by skilful drafting and abundant use of coded language, have laid a veneer of unanimity over what are still divergent and in some respects directly conflicting interests'.
Mr McNamara, who was speaking in a BBC Northern Ireland radio interview, said a great opportunity existed and should be seized. Pointing out that Lord Callaghan, the former prime minister, had also called for clarification to be given, Mr McNamara said Mr Major had already been clarifying things for Unionists in a special article written for the Newsletter, Belfast's Protestant morning paper.
He added: 'If that is going on, it doesn't seem unreasonable that the parties to whom the declaration has been specifically addressed, if they are seeking clarification and not seeking to negotiate, should in fact get that. There is no question of principle involved, because the Government has already been in contact with these people. Peace is too great a prize to be allowed to slip away in this way.'