In the 70s,80s & 90s the ira gave London a hard time too. I got "nicked" just after they bombed the CoL in 94 retreiving a half drunk crate of cans from beneath a skip at the Shell building near Waterloo station. We'd been at a beastie boys gig in Brixton and hadn't drank them all on the way up. Plod wanted to know what the fuck some gobshite with an inderterminate accent was doing retrieving metal cylinders from underneath skips at 1130 at night. Had to prove I was who I said I was. To be sure
They bombed pubs, Harrods, the CoL as I've mentioned. They also, in my anecdotal experience, enjoyed complicit and vocal support from the huge Irish community in London. The difference is there were maybe only a dozen media outlets back then.None of them operated 24-7 and none of them could display shocking images across the globe in milliseconds. Also no social media to give another completely skewed and partial angle to the suffering of our fellow citizens. I think that's why it seems like the end of days this summer. It's not.
My old man ran building sites in the south of England during the 70s and he lost all his (very large) Irish labour force for a week or so now and then, around the time of the Guildford pub bombings and the Harrods attack etc. The local police just rounded up every Irishman they could find and put them in the police cells for a few days until they could confirm who they were, basically interred then. Wouldn't happen now. Point is we've been "under attack" before and cone out the other side. Same will happen this time but the timescale is unknowable at the moment.