Steve Harmison warmed up for the first Test against West Indies next month with another spell full of venom and menace for the MCC, but Sussex were left to rue the damage the England paceman inflicted on their all-rounder Michael Yardy.

With Yardy on 99, a lifting delivery from Harmison left him with a broken index finger on his left hand, an injury which is likely to keep him out for up to six weeks of the reigning county champions' title defence.

After a potent performance on Saturday, Harmison impressed again at Lord's yesterday, finishing with two for 29 from his ten overs from the Pavilion End, and also leaving Sussex nightwatchman James Kirtley with a sore elbow from another viciously bouncing ball.

When the MCC batted, a judicious unbeaten 87 from Owais Shah, featuring 11 fours and lasting 230 minutes, guided them to a lead of 266 with six second-innings wickets intact.

The MCC ended the third day on 226 for four, with Alex Gidman also undefeated on 19, and it remains to be seen whether captain Alastair Cook tries to force a result by declaring overnight.

Despite the best efforts of Harmison and Durham team-mate Graham Onions, whose marvellous spell of three for four in 13 balls in the morning went a long way to giving the MCC a 40-run lead, the pace of the match slackened after lunch.

Without Yardy, Sussex were forced to close their innings shortly before lunch on 385 for nine. But when the action resumed, Sussex had the MCC rattled at one stage, when the impressive Chris Liddle removed openers Nick Compton and Cook during a fiery spell from the Pavilion End.

Alex Loudon followed shortly afterwards for 17, caught by Chris Nash at mid-off after attempting a rash pull off Robin Martin-Jenkins, but Shah and Zoheb Sharif restored order, building a partnership of 84 to ease any MCC jitters.

Shah played well within himself, his half-century - which came from 116 balls and contained six fours - arriving when he turned off-spinner Ollie Rayner to deep backward square-leg and collected an easy single.

Sharif, who was released by Essex in 2004 and has been playing for Cambridge UCCE, had looked comfortable against the off-spin of Rayner.

So it came as a surprise when the slow bowler trapped him lbw for 44.