(CNN) A stash of illegal drugs was found last week in the headquarters of the UK's Home Office, the government department tasked with cracking down on illicit drug use.

The small quantity of suspected Class A drugs was discovered May 3 in a communal area of the building in central London, a Home Office spokesman said Saturday in a statement.

Class A drugs are deemed the most harmful and addictive in Britain and include crack cocaine, cocaine, ecstasy, heroin, LSD, magic mushrooms, methadone and methamphetamine -- more commonly known as crystal meth.

The drugs were found by security staff and no suspects have been identified, a London Metropolitan Police spokeswoman told CNN.

The Home Office is the lead government agency overseeing national security, immigration and passports, drug policy, crime and counterterrorism.

In recent weeks it has come under fire for its handling of the so-called Windrush generation, men and women from the Caribbean who arrived legally in Britain in the 1950s and 1960s but who have struggled to prove their citizenship status amid a recent crackdown on illegal immigration.

The department revealed last month that it had destroyed landing card slips that documented arrival dates for many of the immigrants, creating confusion for descendants who now must prove a citizenship status they previously took for granted.

Home Secretary Amber Rudd quit the top Cabinet post after admitting she "inadvertently misled" a parliamentary committee over targets for the deportation of illegal immigrants.

She was replaced by Sajid Javid, a second-generation immigrant whose parents came to Britain from Pakistan and who is the first member of an ethnic minority to hold the position.

On the same day the drug find was revealed, Javid tweeted a photo of himself with a sniffer dog at London's Heathrow Airport.

"As well as our committed and professional staff, we also have impressive four-legged friends in Border Force like Trigger -- helping sniff out drugs, cash and illicit goods," he tweeted.

A Twitter user, Mat Hudson, replied: "I'd keep him out of the Home Office, Sajid."