Conor O'Shea has launched an impassioned defence of rugby's concussion treatment, admitting he hopes Mike Brown will be passed fit for England's clash with Ireland on Sunday.

Fullback Brown remains locked in a race against time to complete the raft of testing required to face Ireland in Dublin after being knocked unconscious in England's 47-17 victory against Italy.

Brown's Harlequins boss O'Shea backed England's bid to help the 29-year-old win his fitness battle, rejecting recent criticism of the handling of concussion injuries.

Ireland bosses reacted angrily to former France star Laurent Benezech questioning the medical decision around clearing out-half Johnny Sexton to face Les Bleus on Valentine's Day, after an enforced 12-week concussion lay-off.

Former Ireland fullback O'Shea admitted he was nonplussed by some of the commentary around Sexton's return, and hinted he hopes Brown will not face anything similar if he lines up for Sunday's pivotal RBS 6 Nations clash in Dublin.

"If Mike plays, he's fit," said O'Shea. "There's so much conjecture in the media.

"Concussion is a very serious issue, but it's a serious issue which is being treated with incredible sensitivity and commitment by everyone in the game.

"If he goes out on to that pitch, Mike will be fit, and I hope he makes it."

Sexton's club side Racing Metro enforced his 12-week stand-down after the former Leinster star suffered four concussions inside 12 months.

The 29-year-old sat out Ireland's Six Nations opener in Rome, with head coach Joe Schmidt's side easing to 26-3 victory.

Former France international Benezech claimed Ireland were making a "big mistake" sending Sexton back into action against France, especially with wrecking-ball centre Mathieu Bastareaud gunning for a direct confrontation.

Ireland outlined Sexton's recovery in a terse statement before the British and Irish Lions outhalf masterminded the 18-11 victory over France.

Brown was removed by stretcher from the early exchanges of England's 47-17 second-round victory over Italy, watching the second-half action from the bench.

The Harlequins star has suffered several setbacks in his phased concussion recovery, but England bosses still retain the hope he could face Ireland this weekend.

Harlequins rugby director O'Shea said no doctors in the sport are prepared to take any chances where head injuries are concerned.

"Everything is run through the medics," said O'Shea.

"For people to intimate that doctors looking after players would be pressured not to do right by their patient is a very wrong thing to say. And that's the impression I thought certain people were suggesting in the lead-up to the Ireland-France game.

"Some of the stuff said about Johnny (Sexton) was just wrong.

"I hope that Mike (Brown) will be fit, and if he plays, then he will be fit."

Ireland can equal their best-ever winning sequence of ten victories in a row if they can edge past England this weekend.

O'Shea said Ireland beating France and remaining dissatisfied underlines the progress under taskmaster Schmidt.

"I gave myself a little slap across the face when I left the Aviva after Ireland beat France," said O'Shea.

"Everyone was talking about 'it wasn't great, it wasn't this, it wasn't that', and I realised: 'actually I played in a different era for Ireland, and now we've won nine in a row and people are picking holes in it'.

"I played in an era where we would have taken nine in a row very comfortably, and it just shows how far Irish rugby has come.

"I can't call a winner to be honest: I always say to people at the club, I hope the Quins boys are the best players on the pitch, and that Ireland win."