Jack Leach has revealed how his own father passed up the chance to watch his career-best innings in England's thrilling Specsavers Test against Ireland in person, after being scared off by the soaring temperatures.

The United Kingdom experienced its hottest ever July day on Thursday and that was enough for Simon Leach to swap his Lord's ticket for a marathon session in front of the television, watching his son lift England off the ropes with the knock of a lifetime.

The left-hander made 92 after resuming as an unfancied nightwatchman, making a mockery of a first-class record that contained just two prior half-centuries in 108 attempts and an average just under 11.

By the end of day two England were deeply indebted to the Somerset spinner's endeavours, sitting on a 181-run lead and a second-innings score of 303 for nine.

Explaining how his dad had come to miss the big day, Leach said: "He was going to come but he saw the weather forecast and said it was too hot.

"I don't think it would have been a good place for him to be today, he could have died! I think it was best he stayed at home in the cool.

"I gave him my house key and he went over so he's literally been at mine watching the whole time. I'll catch up with him later on."

Leach's stand of 145 with debutant Jason Roy (72) was easily the best of the match to date and he came within a couple of blows of becoming England's first nightwatchman centurion.

In the end he nicked Tim Murtagh to second slip as Ireland's venerable seam attack hauled the game back into the balance by claiming seven for 77 in a superb passage of play, falling eight short of the landmark achievement.

"I know now that the nervous 90s are definitely a thing," he confessed.

"You think 'I'm only two shots away' and I was having some weird thoughts. I was trying to tell myself not to think about it which kind of made me think about it.

"I can't believe it really. I just went out to try and do a job for the team I guess and try and soak up some balls. It probably went a little bit further than I thought it would."

Ireland deserve huge credit for the way they stuck to their task in oppressive conditions, particularly for the manner in which they hauled England back from 171 for one.

It would have been easy to fall back, content with their part in an enthralling see-saw contest, but they were inspired by debutant Mark Adair.

The former Warwickshire seamer removed England captain Joe Root for the second time in the match as well as taking out Jonny Bairstow and Chris Woakes in a crucial phase.

The prize in front of the Test newcomers on day three, an upset for the ages in just their third outing on the big stage, is enormous but the 23-year-old from Holywood was coolness personified as he reflected on his contribution to the cause.

"It's only day two, you can't say it's everything you can hope for yet," he said.

"There's still a result to come out of this game. It'd be good (to win), fairly nice. But we still have to take another wicket. We have to focus on what we need to do."

Invited to wax lyrical about his masterful set-up of Bairstow, which drew comparisons to some of the great overs as the Yorkshireman was teased and tested before being trapped lbw for nought, he was equally non-plussed.

"No. Absolutely not. It was nice to get him but I don't think you can compare it," he said.

"I'm going to tell you something really disappointing here, it was the same plan the entire way through: run in and hit the top off stump. It's so boring, so cliche, but that's what we had to do today."