One of the architects of Theresa May’s “hostile environment” immigration policies, which led to hundreds of West Indian migrants being wrongly denied benefits and deported, was among the former prime minister’s staff handed honours.

Glyn Williams, who was the Home Office’s head of migration policy between 2010 and 2013, when the policies were developed, was made a knight commander of the order of Bath. He was one of 10 Home Office staff named in the Queen’s birthday honours, revealed just hours after May stepped down as Tory leader.

A group of more than 80 MPs last month referred the Home Office to the equalities watchdog over the hostile environment, requesting an investigation into whether the “deeply discriminatory” policies represented institutional racism.

Stephen Doughty, a Labour MP who sits on the Commons home affairs committee, said: “It will be galling to victims of the Windrush scandal and other mess-ups in the Home Office over the past decade to see officials who oversaw these scandals rewarded so handsomely.”

Tim Farron, the former leader of the Liberal Democrats, told the Mirror the honour was “one final insult” to the victims of the hostile environment policies, after he “presided over a litany of mistakes and scandals at the Home Office that saw far too many innocent people detained, deported and denied their rights”.

Williams is director-general of the borders, immigration and citizenship systems policy and strategy group at the Home Office. He sat alongside the former home secretary Amber Rudd, who succeeded May in the role, during her home affairs committee grilling in which she claimed that the department had no targets for deportations.

Rudd was forced to resign after documents emerged showing that the Home Office had set a target in 2015 of 12,000 voluntary departures of people regarded as having no right to stay in the UK – a 60% increase on the previous year.

The revelation prompted concerns that immigration officials may have been under so much pressure to meet the target that legal migrants who struggled to prove their status could have been caught up in the crackdown.

A government spokesman said honours were routinely awarded to public sector employees.