Illegal migrants were employed by gangs to work on land in Tuscany leased from a company owned by Sting, according to an Italian police investigation.

Prosecutors said they believe the pop star was unaware that around 30 to 40 people whose asylum applications had not been processed worked on his land, reportedly for as little as four euros (£3.60) an hour.

The Police star bought an 865-acre estate called Il Palagio near Florence, used to grow olive trees, grapes and other fruit, 16 years ago. His company, Palagio SRL, also owns other farmland, including the area under investigation, which had been leased to another firm and which is geographically separated from Sting's Il Palagio estate.

Labourers from Pakistan and African countries who had not yet been granted the right to settle in Italy were contracted to work there last year by a company associated with gangs, the prosecutor leading the investigation told The Telegraph.

The newspaper said 11 people are being investigated over a number of charges, including commercial fraud, profiting from illegal labour and issuing false financial records.

Sting said he was “saddened and distressed to learn that an independent company leasing some of our fields may have been involved in questionable labour practices”.

“I fully expect that Italian law will take its course and bring the matter to court,” said the musician, whose twelfth solo album, released next month, includes songs about the refugee crisis.

Il Palagio, Sting’s wine estate in Tuscany (Rex) (Rex Features)

The wide-ranging police investigation into labour practises in the region found hundreds of migrants had been illegally recruited between 2011 and 2016 by a group of Pakistanis led by Tariq Sikander, according to Italian news agency Ansa.

Antonio Sangermano, at the head of the wide-ranging investigation into labour practises in the region, told The Telegraph Sting “had no knowledge of this and we believe he was not even in Italy at the time.”

“He is not part of our inquiry. But we are looking into exactly who employed these workers on the estate,” he said.

Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis Show all 7 1 /7 Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis The Solidarity With Refugees group said Saturday’s protest aimed to “show our Government and the world that Britain is ready to welcome more refugees”. Rex Features Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis People march through central London as they take part in a protest rally organised by Solidarity with Refugees in a bid to urge the Government to take more action on the migrant crisis Press Association Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis The protest comes days before world leaders meet to discuss crisis at UN General Assembly Press Association Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis Demonstrators made their way from Park Lane to Parliament Square in London on Saturday afternoon Press Association Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis Marchers chanted “refugees are welcome here” and waved banners reading “no-one is illegal” and “let’s help people” Press Association Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis The march was supported by charities and groups including the Red Cross, Asylum Aid, Save the Children, Hope Not Hate, Oxfam and the UN Refugee Agency Rex Features Refugees welcome here: Protesters demand UK resettle more migrants in response to refugee crisis In the wake of Alan’s death, David Cameron pledged to resettle 20,000 Syrian refugees in the UK over the coming five years but there have been additional calls to re-home those who have already reached Europe, as well as asylum seekers coming from other conflict zones such as Iraq and Afghanistan Rex Features

The investigation started last May after two refugees reported the operation, according to Corriere della Sera.

They said a vehicle carried the migrants staying in the town of Prato straight to vineyards before dawn each day.

The newspaper reported that three directors of the company Coli Spa, believed to be at the centre of the operation, have been arrested.