A LONG-RUNNING inquiry into alleged bribery and corruption involving Mariano Rajoy’s People’s Party (PP) has heard claims that the Spanish prime minister and PP general secretaries had received money from an alleged slush fund.

Manuel Morocho, chief inspector of the Unit of Economic and Financial Crimes (UDEF) of Spain’s National Police, told a congressional commission that the “Gurtel” case was “corruption in its purest form”.

It involves the PP’s alleged use of a parallel system of accounts – extracts of which have been widely published – to syphon money paid in bribes to finance the party through what is known as box B, which was handled by former treasurer Luis Bárcenas.

Carolina Bescansa, spokesperson of the left-wing Podemos, asked Morocho who had received the payments from box B, and named Federico Trillo, the former Spanish ambassador to the UK, Francisco Álvarez Cascos, former PP general secretary and Rajoy, as well as the general secretaries of the PP.

Morocho replied: “Yes,” adding that the evidence in the cases of Trillo and Rajoy was “indiciariamente” – circumstantial.

Morocho said the Spanish Treasury had carried out the procedures to ratify the income in box B.

“An organisation that has operated for a long time, which has penetrated to very deep levels in public administrations until it has become parasitic and absorbed the capacity of a political leader to allocate and manage public funds ... that is, the concept of corruption in its purest form,” he added, describing the Gurtel network.

He said it was active mainly in Madrid and Valencia, and always worked in the same way: “Companies awarded public works that assumed the cost of advertising and electoral events of the local political formation for a specific electoral campaign ... through the mechanics of generating contracts or invoices for alleged services provided by the companies of Francisco Correa to these construction companies and that allowed him to go abroad to justify a transfer of funds.”

The inquiry has been running for more than a decade, and Morocho told the commission the UDEF had been subject to “destabilising” pressure to try to halt its investigation, which required budget, human resources and operational independence. He said he received a number of complaints from those under investigation, all of which were archived.

“The objective was very clear, to destabilise the investigation,” he said.

Anti-corruption prosecutor Concepcion Sabadell earlier said it had been clearly shown that PP had used the parallel accounting to finance the party. She said: “There is solid proof that the PP has benefited from criminal activity in the town hall of Majadahonda (near Madrid): the PP, not the local authority.”

Sabadell said Barcenas was a key player in the scandal, and added that the former PP mayor of Mahadajonda, Guillermo Ortega, had obtained €1.6 million (£1.4m) from alleged bribes but had not “given a reasonable explanation of its origin”.

She added that Barcenas, who accumulated €48.2m (£42.6m) in Swiss bank accounts in 2007, had obtained “funds of an illegal origin and hidden the benefits with false bills”.

Rajoy made history in July when he became the first serving Spanish prime minister to give evidence in a criminal case. Developments – which were not reported by Spanish state television – came as Spain’s foreign minister said a nationwide vote could be held on independence for Catalonia and other regions in the future.

Alfonso Dastis told the BBC the possibility of a country-wide vote was in recognition of events in Catalonia, where Rajoy used unprecedented constitutional powers to sack the Catalan government and detain a number of its deposed cabinet members following its declaration of independence.

“We have created a committee in parliament to explore the possibility of amending the constitution to be able to accommodate better the aspirations of some of the Catalan people,” said Dastis.

“We acknowledge there is a political situation that deserves to be looked at but, in any case, it’s clear that the decision will be taken, will have to be taken by all Spaniards.”

Dastis had previously described pictures of state police beating Catalans trying to vote as “fake”, and said he was sorry if people got hurt.

All Spaniards voting on Catalan independence is unlikely to be a welcome gesture.

Sources close to deposed Catalan President Carles Puigdemont are unlikely to comment.