Pakistan's Azhar Ali made an unbeaten double century as he helped Worcestershire rewrite the record books in an English County Championship match against Leicestershire on Friday.

Azhar and former England Under-19 international Jack Haynes put on 281 for the third wicket -- a record partnership against Leicestershire, surpassing the 278 by Cyril Walters and Harold Gibbons in 1934.

Their stand was the cornerstone of Worcestershire's 456 for three, a lead of 308, at stumps on the second day of four at New Road.

Haynes was eventually dismissed for 127 but Azhar reached his double century in the final over of the day with a cover drive for four off Rehan Ahmed.

By that stage Azhar had faced 328 balls, with one six and 18 fours, and also shared in another century stand with Brett D'Oliveira (52 not out).

Azhar arrived at New Road, Worcestershire's headquarters, after a successful Test series against Australia which included a marathon 185 spanning 11 hours at Rawalpindi.

The 37-year-old struggled at first with the change to English conditions and his opening six innings for Midlands county Worcestershire yielded 34 runs.

But the former Pakistan captain has found his form since hitting 92 against a Durham attack including new England skipper Ben Stokes.