The woman once seen as a potential successor to Spanish Prime Minister Mariano Rajoy — who was embroiled in a scandal over an allegedly fake degree — has resigned as head of the Madrid region following new allegations that she was caught shoplifting seven years ago.

Video has come to light apparently showing Cristina Cifuentes, the conservative president of the Madrid region, being questioned by supermarket staff over the alleged attempted theft of cosmetic products in 2011.

As she quit her post on Wednesday, the politician described what happened as "involuntary".

The episode adds to the current misery for Rajoy’s Popular Party (PP), already fragile and relying on opposition backing to pass legislation.

Until recently Cifuentes had been viewed as one of a select few potential candidates to succeed the prime minister. However, she is now seen as damaged goods — and her resignation leaves Rajoy in an even more vulnerable position.

Brought down by two tubs of cream

The three-minute video, published on the Spanish website OKDiario after what it says were several weeks of investigation, is said to have been filmed in May 2011 in a back room of an Eroski supermarket near the Madrid regional assembly, where Cifuentes was deputy speaker at the time.

It shows a woman going through the contents of a shopping bag in the presence of a security guard. She takes out a wallet and appears to pay the guard, who hands something to another guard who has entered.

The website said it has no doubt that the woman in the video is the current premier of the Madrid region, and other media say sources close to the politician have admitted it is her.

According to OKDiario, Cifuentes was held for 45 minutes by supermarket staff on suspicion of having taken two cans of an anti-ageing cream without paying. They were apparently surprised that such a well-dressed woman with “Prada shoes” should try to swipe products worth barely 40 euros.

The website claims that at first the politician denied stealing, claiming the creams were already in her bag when she entered the store. Staff — who reportedly did not recognise her — then called police.

Two plainclothes officers duly arrived after 45 minutes, and immediately realised who she was. They called their superiors for advice, and were told to release Cifuentes immediately. It was at that stage that she is said to have paid for the products before being allowed to leave the supermarket discreetly via the back door.

Eroski considered the matter closed, while police — who never requested the security footage — took no further action, according to the report.

Cristina Cifuentes and PP leader Mariano Rajoy at a campaign rally in Madrid, December 2015 REUTERS/Juan Medina

More grief for Rajoy

The separate scandal involved a master’s degree Cifuentes allegedly obtained fraudulently from the King Juan Carlos University (URJC) in Madrid in 2012, having supposedly never attended classes or taken exams. She returned the qualification, denying having done anything wrong and blaming the university for any irregularities.

Before resigning on Wednesday, Cifuentes said taking the cream had been an “involuntary thing”.

However, she sought to play down the video’s importance, claiming she was the victim of “harassment and demolition that has gone beyond politics”.

Her departure further puts at risk the PP’s tenuous grip on power in the Madrid region. The conservative party only controls the regional assembly thanks to the support of the centre-right Ciudadanos (“Citizens”), which has taken a hard line on corruption.

Mariano Rajoy said Cifuentes had “done what she had to do”.