Britain on Saturday honored members of the so-called Windrush generation, people from the Caribbean who were encouraged to migrate here to help the country rebuild after World War II, but struggled to prove their citizenship in a recent immigration crackdown.

On Saturday, which was declared the first National Windrush Day, Prime Minister Theresa May of Britain announced that a memorialto their efforts would be built at Waterloo Station, where many immigrants first arrived in London after docking at Southampton. It was also where they met friends and family member who had already settled in Britain.

Mrs. May called the occasion an “annual opportunity to remember the hard work and sacrifice of the Windrush generation.”

“They crossed an ocean to build a future for themselves, for their communities, and above all for the United Kingdom — the country that will always be their home,” Mrs. May added.

But the tribute on Saturday was overshadowed by criticism of the government’s immigration policy and by the lingering effects of a clampdown on members of the Windrush generation last year.

And the prime minister’s tribute video drew a backlash, with critics reminding the public of Mrs. May’s legacy before she became prime minister. As minister responsible for immigration, Mrs. May championed a “hostile environment” policy intended to make life in the country difficult for undocumented migrants and to dissuade potential arrivals.

The Windrush name comes from the ship that brought the first large group of residents from British colonies in the Caribbean to the country in 1948, at the invitation of the government, to fill a postwar labor shortage. More followed, many with children, over the next quarter-century.

Though born in colonies, they held British citizenship under the laws in force at the time, and were entitled to live and work in Britain. Many arrived as children on parents’ passports. But those who could not prove that they had arrived before 1973 lost jobs, were denied medical care, were evicted or detained, and even threatened with deportation.

After personal stories surfaced in the British news media, the government backed down and apologized.

[Read: Renford McIntyre was made homeless after the governmentdeclared him an undocumented immigrant.]

The government set up a grant of 500,000 pounds, about $640,000, last year to help towns and cities across the country organize street parties, exhibitions and talks for national Windrush Day.

The government also vowed to help Caribbean-born residents with a hardship fund of up to £200 million, but compensation has been dribbling out, according to The Guardian. Only 13 people had received any compensation as of early this month.

On Saturday, Sadiq Khan, the mayor of London, posted a video message posted on Twitter in which he called out the “disgraceful” treatment of the Windrush generation, saying it “will go down as one of the most shameful episodes in our history.”