But after crossing in the first half through New Zealand wing Rico Gear, Worcester hit back in the second and penalties from Loki Crichton and replacement Shane Drahm brought the game to within one point.

And despite some ferocious late pressure Brian Smith's men hung on for their sixth straight win which sends the Exiles up to sixth in the table.

Worcester meanwhile remain rooted in their relegation dogfight with Leeds and were once again made to pay for their indiscipline.

Twice in the opening stages they conceded needless penalties but they were not to pay as Delon Armitage, on his 100th appearance for Irish, missed both kicks.

But when referee Rob Debney penalised the home side for crossing the kicking duties changed hands.

This time Hewat stepped up and made no mistake to give the Exiles a 13th-minute lead and that was doubled after Drew Hickey spoke out of turn to referee.

After 31 minutes, Warriors roared back into the game with a Gear try in the corner following a strong rolling maul and some good interplay with left wing Miles Benjamin.

But Crichton missed the conversion and Hewat extended Irish's advantage to four points with another penalty after Worcester had been penalised for collapsing a scrum.

London Irish started the second-half by stealing a Warriors line-out and Hewat slotted a drop-goal.

The Warriors' comeback began when Mike Catt dwelt on his clearance which allowed Kai Horstmann to charge the ball down and, although Irish secured the ball, they were penalised for not releasing and Crichton pulled the score back to 12-8.

Hewat could have given Irish some breathing space but blotted his copybook by missing a penalty after Tevita Taumoepeau had been spotted coming in at the side.

Warriors' replacement fly-half Drahm went straight into the action after coming on for Crichton, slotting a 35-metre penalty after Irish had strayed offside.

There was a let off for Drahm as his wild inside pass flew straight to Richard Skuse, who surged to the Warriors line before knocking on.

In the last minute, Marcel Garvey won Worcester a line-out when his kick through was carried into touch.

Warriors won the line-out and staged a late rally, but the Irish defence held firm leaving the hosts to settle for a losing bonus point.