Stand-in captain Courtney Lawes insists England will "relentlessly" strive for improvement and "won't give up" following another major jolt in their bumpy road towards the World Cup.

Head coach Steve Borthwick is sweating on the availability of two key players ahead of the tournament in France after Billy Vunipola's red card in Dublin compounded Owen Farrell's disciplinary saga.

England struggled to convince with 15 men at the Aviva Stadium before Vunipola's 53rd-minute dismissal for ploughing into the head of Andrew Porter helped the world's top-ranked team cruise to a 29-10 success.

Yet flanker Lawes, who skippered his country as Farrell watched on from the stands, believes there were "a lot of positives" to take from a meek display.

"It's obviously very disappointing," he said. "The thing is if we just get certain things right in that game, it's very different, it's a very different game - and they are all things that we can control.

"But we have to be able to control them. There are obviously a lot of positives, which is great.

"If we tidy up a couple of areas, we'll be a much different team and we've proved we can hang with the best as long as we get them right. But it doesn't make it any less disappointing that we didn't get it right.

"We won't give up. We will relentlessly pursue the betterment of our team and that's all we can do."

England rarely offered a try-scoring threat on Saturday evening and were 12-3 behind at the break following scores from Bundee Aki and Garry Ringrose.

Matters took a turn for the worse shortly after the restart when Vunipola's shoulder-led tackle was upgraded from a yellow card to a red on review.

Tries from James Lowe and Mack Hansen stretched Ireland's lead before Keith Earls added to the misery on the occasion of his 100th cap after Kyle Sinckler crossed for a consolation.

England should discover the fates of Saracens pair Vunipola and Farrell before hosting Fiji at Twickenham next weekend, with their World Cup campaign set to begin against Argentina on September 9.

Borthwick was unsure how much the uncertainty surrounding Farrell, who is awaiting the outcome of World Rugby's appeal of the decision to overturn his red card against Wales, impacted England's performance against Ireland.

But he accepts his team need greater cutting edge as they seek to turn winning into "a habit".

"It's always difficult to accurately evaluate that because it's an unknown but it certainly hasn't helped our preparation this week and we're going to have to deal with it again this forthcoming week," he said, referring to Farrell's situation.

"We're going to have to ensure we minimise any disruption and distraction of it to get the performance we want.

"We play against Fiji back at Twickenham next week and we want to make sure we get a win, we want to make sure we get an improved performance because winning is a habit and we want to make sure we start building that habit.

"The area we've seen we need to see more improvement is that conversion of opportunities in the final third.

"Do we want to see more progress? Absolutely. And that's what we'll be focusing our attention on over this coming week and beyond as we build into that first game of the World Cup."

*copy from Press Association.