LONDON, Sept 15 (Reuters) - British Prime Minister Boris Johnson reshuffled his senior ministers on Wednesday, appointing his party"s first female foreign secretary, as he urged his government to get on with the job of tackling economic inequality after COVID-19. Ending regional inequality is key to the agenda set in 2019 when Johnson won the biggest Conservative Party parliamentary majority since Margaret Thatcher. But the issue has been eclipsed by COVID-19 and headlines about ministerial gaffes. The replacement of Dominic Raab with former trade minister Liz Truss at the Foreign Office underlined the rationale behind the reshuffle - move those whose blunders have buffeted the government and promote those who have avoided crises. "The Cabinet I have appointed today will work tirelessly to unite and level up the whole country. We will build back better from the pandemic and deliver on your priorities," Johnson said on Twitter."Now let’s get on with the job." Finance minister Rishi Sunak remains in his post, as does Brexit minister David Frost. Truss, a favourite in the Conservative Party, moves to the Foreign Office from the trade department where she completed a number of trade deals since Britain left the European Union. She is the second woman to serve as foreign secretary, following Margaret Beckett, who held the post from 2006-2007 in a Labour government. Anne-Marie Trevelyan moves to trade after being climate minister. read more AFGHANISTAN Truss" predecessor, Raab, has faced calls to resign since he went on holiday in Crete as the Taliban advanced on the Afghan capital, Kabul. He was demoted to the Justice Ministry. To soften the blow, Raab was also appointed deputy prime minister, a role he played in all but name when he stepped in to lead the government when Johnson was fighting for his life in hospital with COVID-19 last year. Michael Gove, seen as a key player in the Johnson government, was moved to housing from his position in the Cabinet Office, a department at the centre of government that drives the implementation of policy. He was replaced by Stephen Barclay, a former Brexit minister. Raab"s and Gove"s moves followed the sackings of three others: Gavin Williamson as education minister, Robert Buckland as justice minister and Robert Jenrick as housing minister. Buckland had not committed any gaffes or been criticised over his decision-making, but was moved to make way for Raab. Williamson"s downfall had been widely expected after he was criticised for his handling of school closures and exams during the COVID-19 pandemic and for confusing two Black campaigning sportsmen. read more Jenrick had been under fire over his role in a 1 billion-pound development proposed by a Conservative Party donor. Some in Johnson"s party had suggested the much-rumoured threat of a reshuffle helped ensure that his plans for a tax rise to tackle a crisis in health and social care got party backing after it was widely criticised for hurting the lowest earners the most. The party has since slipped in opinion polls and one of those replaced on Wednesday was its chair, with former culture minister Oliver Dowden taking over the post. Critics accused Johnson of seeking to overshadow the opposition Labour Party"s planned vote in parliament on the government"s decision to scrap extra support for low-income families. But some Conservative lawmakers said it had been simply long overdue. One lawmaker, speaking on condition of anonymity, described the Cabinet as a boat that was "appallingly encrusted with barnacles".