John Major worked on it from 1993-1997 and took us from an adversarial point to the UK and Ireland working towards peace. There wasn’t a massive amount of grandstanding about it especially towards the end of his premiership as he was a weakened PM and if it had run into significant opposition in either UK or NI it would have finished it off.
John Major did all of the hard work and diplomacy getting it to May 1997 and normalising UK/Ireland relations. There wasn’t a huge deal about it because pre-1997 and the birth of ‘spin’ politics was done very differently. What it did need for the final stages was a government with a strong majority to push through the final stages which is what Blair did.
Major and the Tories actually did most of the difficult diplomacy repairing the damage of the Thatcher years well before Blair was in power.
If you’ve fallen for the lie that peace in NI only came about because of new Labour then you have fallen for spin. And yes, Tony Blair did take the credit because he has always been incredibly vocal about how he ‘brought peace’ to NI, particularly when he is trying to convince people he is capable of bringing peace to the ME. And his level of success there is perhaps a better indication of his statesmanship than a 3/4 finished job he tied up the tail end of.
People may say ‘oh, I remember, Labour did it all and it wouldn’t have happened if it wasn’t for them’. But you’re actually remembering the spin you were told and not the facts.
It was Major who first started the dialogue with the IRA that led to peace too:
www.google.co.uk/amp/s/amp.theguardian.com/uk/1993/nov/28/northernireland
Forget what you think you remember, go and do some proper research from unbiased sources rather than relying on half remembered Labour spin.