With connections to former Downing Street chief of staff
Sue Gray, there has been speculation her cabinet role could be under threat in a future reshuffle.
Ms Gray's son, Labour MP Liam Conlon, is Ms Haigh's parliamentary private secretary and acts as her "eyes and ears" in parliament, while another of her former employees also worked for the former chief of staff before she was sacked after losing a power struggle within Number 10.
As transport secretary, Ms Haigh was one of a handful of cabinet ministers who complained to the Treasury about impending cuts in the budget.
She is considered to be one of the more left-wing members of the cabinet and has vowed to "rip up the roots of Thatcherism" with her plans for rail and bus reform.
In 2015, Ms Haigh was one of a number of Labour MPs to nominate Mr Corbyn for leader - a decision she later said she regretted.