LONDON — Heidi Alexander has been appointed U.K. transport secretary following the shock resignation of Louise Haigh Friday. The MP for Swindon South returned to the House of Commons at the general election in July, having previously represented the constituency of Lewisham East between 2010 and 2018. She was named as senior minister in the Justice Department in new Prime Minister Keir Starmer’s first government lineup before being appointed to the Cabinet following Haigh’s fall from grace. The 37-year-old Haigh had been the youngest member of the Cabinet before becoming the first to quit. It emerged late Thursday she had…