He was tipped off by Lord Shaftesbury to withdraw a large sum of money from the Treasury before the Government suspended payment, and when Backwell was ruined because of the suspension, Duncombe took over his premises in Lombard Street at the sign of the Grasshopper.He was appointed to a committee to investigate the prices of coal in London and in February 1703 he handled his constituents' petition for an extra market day at Downton.He was fairly inactive in Parliament but in the City of London he came under attack from Whigs who removed him as a militia colonel, and his mayoral ambitions were overlooked by the court of aldermen.[6] In May 1709, he endorsed the candidacy of Dr Henry Sacheverell for the chaplaincy of St Saviour's, Southwark and later showed Tory partisanship by reportedly giving only £50 for the relief of the Palatine refugees, and only for the sake of his office.Though generally known for support of charitable causes and praised by the poor debtors of the Wood Street compter for his help while Mayor, the Palatines were a Whig cause.He was returned as MP for Downton at the 1710 British general election, and was later cited as one of the ‘worthy patriots’ who in the first session of the 1710 Parliament helped to detect the mismanagements of the previous administration'.