The Queen invests Charles as Prince of Wales at Caernarfon Castle
A row has broken out over a march to commemorate two men killed by a bomb they were carrying on the eve of the Prince of Wales' investiture in 1969.
Conservative politicians criticised the event marking the deaths of George Taylor and Alwyn Jones near government buildings in Abergele, Conwy.
Clwyd West AM Darren Millar said he was appalled North Wales Police had offered to police Saturday afternoon's event.
Police said the event passed off peacefully with minimal disruption.
The force said they had not made the offer to police the event but had a duty to ensure safety.
A spokesman said 80 people attended and Market Street was closed for only a few minutes.
The two men died just before the investiture on 1 July 40 years ago.
Press reports at the time said they had set off with the "apparent intention" of placing the bomb near the route of the train carrying members of the Royal Family.
The march has been promoted on social networking site Facebook, in which the two men are called members of Mudiad Amddiffyn Cymru ( Movement for the Defence of Wales).
The Facebook posting says the group organising the event "does not promote violence" but "debate about Welsh history and politics".
It also adds: "We would like to make clear that under no circumstances are we calling for the actions of these men to be repeated".
Mr Millar said he was disgusted that "an event to commemorate terrorism" was taking place in his constituency.
"I'm further appalled that the north Wales force have offered to police the event," he said.
'Lawful and impartial'
"This will be particularly unwelcome given the force's recent decision to withdraw free policing support to the popular Abergele carnival - which has now been cancelled as a result."
North Wales Police said they had not offered to control the march but it was their duty to police such events in a proportionate, lawful and impartial manner.
"To achieve this we have been in contact with someone purporting to be organising the event in order that we can lay down ground rules to minimise disruption and ensure the safety of the local community, participants and police officers alike", said Chief Inspector Rob Kirman.
Clwyd West Conservative MP David Jones said he did not agree with commemorating the men, and it would anger local families.
"I think local people will be appalled," he said.
"But the police do have a positive duty to police (the march) and it's a free country. The problem is it puts extra pressure on the police"
John Jenkins, a former leader of MAC, said the two men did not intend to bomb the royal train.
Mr Jenkins, who was jailed for 10 years in 1970 after pleading guilty to eight charges relating to explosives and conspiracy, told the Western Mail: "I've made it clear all along that there was no threat to the prince at all.
"Our priorities were about hearts and minds and awakening national consciousness and this would hardly have been helped by targeting people at any stage."
A verdict of accidental death was recorded at the inquest in October 1969 on the two men.