Londoners' chances of getting on the property ladder are being damaged, argue west London politicians, after it emerged that property agents were marketing homes overseas first.

MP for Kensington Victoria Borwick and Uxbridge MP Mayor Boris Johnson have raised their concern as new evidence emerged to show the scale of overseas marketing of new homes built in London.

According to the investigation, top property agents had hosted "cocktail parties" to promote Westminster property to buyers in Hong Kong and Singapore.

MP Borwick said: "New homes should be marketed to Londoners first.

“We must not dissuade foreign investment in the capital but we must ensure that Londoners can buy property in places like Kensington before it is being offered abroad as an investment opportunity.”

In support of Londoners being sold housing first, Mayor Boris Johnson signed a voluntary contract with developers to urge them to sell all new homes to Londoners before or at the same time as overseas buyers.

However, not all developers signed the Concordat, leaving some agents free to market abroad in central London first.

In a parliamentary debate on the Housing Bill on Tuesday (January 5), Labour mayoral candidate Sadiq Khan pushed for a percentage of newly built homes to be allocated to people living locally .

Mr Khan said: "I'm fortunate to live near my family around the corner from the council estate where we grew up.

"But it's much harder for young Londoners today."

Highest deposits in UK

The investigation, led by the Labour party, revealed top property agent JLL held no fewer than 40 events to promote London property.

Over a quarter of the events were held at Hong Kong's five star Mandarin Oriental Hotel, where visitors were invited to view apartments as part of a three day series.

Developments in west London being showcased include properties in Kensington - London's most expensive spot - Westminster Quarter and Embassy Gardens.

A recent report carried out by the Mortgage Advice Bureau showed that average deposits in London are currently the highest in the UK , at a whopping £179, 248.

Mr Khan added: "This investigation reveals the shocking scale of London homes being sold to overseas investors, rather than to the Londoners who desperately need them.

"My plan will ensure that Londoners get first dibs on new homes built in the capital, rather than overseas investors.

JLL were approached for a comment and are yet to respond.