London commuters have criticised a large flashing sign outside Waterloo station, which which purports to be from the police and discourages giving money to beggars.

One user called the sign "absolutely ridiculous" while another said "not in my name".

Another person tweeted: "What a disgraceful sign the @metpoliceuk installed outside Waterloo... is this how we treat #homelessness, as #beggars ???"

In the past, monitors on the Tube which are normally used to denote status updates have had a message added warning commuters not to "encourage the presence" of beggars and buskers who may be on the London Underground.

The Metropolitan Police had not commented on the sign at the time of publishing.

London-based Thames Reach warns not to give money to beggars as it says it does more harm than good.

"Overwhelming evidence shows that people who beg on the streets of England do so in order to buy hard drugs, particularly crack cocaine and heroin, and super-strength alcoholic beers and ciders. These highly addictive drugs cause an extreme deterioration in people's health and even death," it states.

However, many people argue this reinforces negative stereotypes about homeless people.

More than a quarter of a million people are homeless in England, according to the latest research by homelessness charity Shelter.