In 1692[1] or 1693,[2] possibly using the wealth he acquired by his marriage, he purchased Biddesden House at Ludgershall in Wiltshire, an estate which carried with it the decisive electoral influence over the pocket borough of the same name.
In September 1708, commanding the British troops at the Battle of Wijnendale, he succeeded in protecting a convoy from superior French forces and delivering supplies to the besiegers of Lille, which led eventually to the town's capture; but opponents of the army commander, Marlborough, accused him of giving the credit in his initial dispatch to Webb's Whig subordinate, William Cadogan, for political reasons.
In 1709, Webb served at the Battle of Malplaquet, where he was severely wounded; he was awarded a substantial pension and returned to England, seeing no further active service.
Unable to expect re-election at Newport under the new Governor, his old rival Cadogan, he was forced once more to fall back on the family seat at Ludgershall, which he represented again from 1715 until his death.
His eldest son by his second wife, also named John Richmond Webb (1721–1766), was a lawyer, and briefly a judge and Member of Parliament.