Police feared Andrew Mountbatten-Windsor could stop their raids on his homes by saying they needed to speak to his brother the King, documents reveal.

Before Thames Valley Police swooped on Sandringham and Windsor, they were worried they would be sent packing without a search warrant.

They obtained warrants from an Old Bailey judge, telling him Andrew or his lawyers could block their entry by saying 'that the property belongs to someone else (the King) and that separate legal permission should be sought'.

Officers were concerned that evidence could be lost, if they were delayed by having to seek permission from Buckingham Palace to search the one-time Duke of York's properties.

The details emerged in legal documents obtained by the Daily Mail concerning Andrew's victory over police who raided his homes.

The High Court has agreed to a request by the Mail to release documents in the royal's legal battle against Thames Valley Police and the Old Bailey judge who approved the searches at Sandringham and Windsor.

The Detective Chief Inspector (DCI) in charge of the raids told the Old Bailey judge that Andrew was a 'suspect in a number of serious offences', adding that 'it is a matter of public record that he has previously not engaged with other investigative strands relating to his alleged involvement with Jeffrey Epstein'. 

Andrew's lawyers insisted this was 'materially and factually incorrect'. The former duke has not been charged with any offence.

The DCI, whose name was not made public, said: 'My investigative objectives are to secure relevant evidence in a timely and secure fashion. Failure to do so risks loss of evidence and a consequent loss of public trust and confidence in the investigation.'

The senior officer stated that items in Andrew's possession were 'likely to be of significant value to the investigation'.

As police could not be sure they would be allowed access, without a warrant, the officer asked the judge to grant one, saying: 'I have no way of any degree of certainty that AMW or his legal representative will grant entry to the premises or, were they to do so, whether they would seek to frustrate certain elements of [the searches]'.

Thames Valley Police made the search warrant applications on February 18, the day before officers launched the early morning raids. The Recorder of London, Judge Mark Lucraft KC, approved the search warrants. 

Extracts from the applications were revealed in the case papers presented to him.

These said the DCI 'had reasonable grounds for believing that [Andrew] had committed an offence of misconduct in public office'.

While he was the UK's trade envoy, in 2010, he 'forwarded official reports…to Jeffrey Epstein within minutes of receiving them'. The reports had been sent to Andrew in relation his official trips on behalf of the British government to Singapore, Vietnam, China and Hong Kong.

It was also said that Andrew, whilst trade envoy, had held a meeting with a private investment firm in 2011 in which he suggested Epstein might invest in the firm.

These amounted to 'inappropriate and unlawful disclosure of material whilst holding a public office', said the police. The royal's lawyers contested this, saying there was no reason to state it was inconsistent with his trade envoy role.

It emerged last week, on October 8, that the King's brother had won a judicial review challenging the police and court, with the High Court ruling that the police raids had been unlawful.

The documents released today reveal that Andrew's lawyers argued the searches had not been lawful, for several reasons. Among them, they said there was no reason for saying the former prince would not cooperate. There was also 'no proper basis' for concluding that he might destroy evidence.

They also said the release of the Epstein Files in February this year, when details of Andrew's emails to the financier were revealed, would have given Andrew or others 'plenty of notice and opportunity to dispose of evidence should they have been inclined to do so'. 

The ex-Duke's lawyers added that the police had breached their duty to provide them with details of their warrant application to the judge.

The legal drama threw into doubt the ongoing investigation by Thames Valley Police into Andrew and his dealings with convicted sex offender Jeffrey Epstein. But Andrew is not in the clear, with police - who admitted mistakes in their warrants - asking a judge for permission to retain documents and electronic devices that were seized.

The disgraced former prince was arrested on his 66th birthday in February and quizzed for nearly 12 hours at Aylsham police station. He was questioned on suspicion of misconduct in public office.

Six days of searches ensued at Royal Lodge, the Windsor home he was forced to give up after more than 20 years, and at his then-residence, Wood Farm on the Sandringham Estate in Norfolk.

The one-time Duke of York has been seen only fleetingly since, having now settled into nearby Marsh Farm. But in an extraordinary hearing at the High Court on October 8, details emerged of his legal challenge. 

It became clear that Andrew had applied for a judicial review, asking a judge to rule that the police swoops on his homes were unlawful. He listed five grounds, only one of which has been made public - that some of the material seized might have been held by him 'in confidence'.

The one-time Duke of York has been seen only fleetingly since, having now settled into nearby Marsh Farm. But in an extraordinary hearing at the High Court on October 8, details emerged of his legal challenge.

The one-time Duke of York has been seen only fleetingly since, having now settled into nearby Marsh Farm. But in an extraordinary hearing at the High Court on October 8, details emerged of his legal challenge.

The challenge was pursued at the High Court earlier this year, but without the public being told anything at the time.

Thames Valley Police conceded that the search warrants had been unlawful and Mr Justice Hilliard formally quashed the search warrants in a ruling behind closed doors on July 22.

When the story finally emerged, Thames Valley Police blamed the fiasco squarely on the Old Bailey judge who had approved the search warrants.  

In theory, the force could be made to return all of Andrew's belongings seized in the raids. Such a move would deal a potentially fatal blow to the misconduct in public office investigation that was launched after the publication of the Epstein Files this year. 

But Thames Valley Police has made a separate application to be allowed to retain the material, and has vowed its investigation would continue.

After admitting the raids were unlawful, police applied on June 4 for permission to keep Andrew's belongings anyway.

They must show there is a legitimate reason for them to retain them. This application will be heard by the same judge but not until next year.

Andrew was questioned about his time as the UK's trade envoy, a role he held between 2001 to 2011.

Emails suggested he had shared government information with his Wall Street friend, convicted paedophile Epstein.

In a remark about when the police would complete their investigation, Mr Justice Hilliard said: 'I suspect that is quite a way off.'