LONDON, U.K. - Hit by an embarrassing data breach, the British Prime Minister Theresa May's Conservative Party has said that it has launched an investigation into the cyberattack.

In a breach that was first spotted by a columnist with the Guardian newspaper, Dawn Foster, a flaw in the Conservative Party's mobile app allowed users to log in as a user attending the party conference.

To log in, users merely required to enter an email address - which means that anyone could log into the app as a senior government ministers and view their personal details. 

Further, the flaw allowed anyone who logged in receive access to the mobile phone numbers of all those attending the four-day event.

This included everyone from journalists, party members and lawmakers, including senior government ministers. 

Revealing the flaw on Twitter, Foster showed her followers that she had been able to log into the system as former foreign secretary Boris Johnson.

She wrote in a tweet, "It's let me login as Boris Johnson, and just straight up given me all the details used for his registration. I'm the most tech illiterate person alive, and I've done this, imagine there are plenty more security bugs."

After the flaw was pointed out to the party, the loophole in the app was reportedly taken down.

However, by then, some details of some top politicians had been accessed and some were even changed. 

Further, a report in BuzzFeed pointed out that at least two cabinet ministers had received prank calls from the public.

Commenting on the flaw and the incident, a Conservative spokesman said in a statement, "The technical issue has been resolved and the app is now functioning securely. We are investigating the issue further and apologize for any concern caused."

On Sunday, in an interview with Sky News, party chairman Brandon Lewis said, |Any breach is a serious breach that's why we are fully investigating it and are taking it very seriously."