Despite David Cameron’s experience as a marketing man, his skills at reputation management were feeble compared to those of Theresa May. May was not a terrible Home Secretary but she was not a good one, still less an outstanding one.

Yes, she remained in office for six years. But longevity in office is hardly proof of success, even at the Home Office. Anyone who has worked in a large organisation has encountered long-serving, apparently unfireable incompetents, and one thing that the history of the Cameron administration surely proves is that being bad at your job rarely leads to losing that job.

Some kind of strange magic has prompted pundits and analysts to forget all the misfortunes and scandals of her tenure. Now seems a good time to remember them, and to consider the type of leadership style that they suggest.

To begin with there was the outcry over a relaxation of border checks on non-EU nationals that came about because of ‘unauthorised actions’ by a head of the Border Force who took a sensible pilot scheme too far. Later came the absurd vans carrying billboards telling illegal immigrants to leave. Then, the strange, secret advice deal with Saudi Arabia’s interior ministry that involved Mrs May travelling to that country whose criminal justice system is infamous for its barbarity and medieval cruelty. After that came the mistreatment of female asylum seekers by Home Office contractors at the Yarl's Wood detention centre, a scandal that deepened when Mrs May banned the UN’s special rapporteur on violence against women from visiting the centre.

There was also Mrs May’s decision to opt into the European Arrest Warrant, which allows immediate extradition without prima facie evidence to EU countries, some of which have corrupt, third-world style judicial systems. And in the case of the three radicalised British schoolgirls who flew to Turkey to join Isis, their recruiters were correct in predicting that they would be able to leave the country undetected. (Three years later, the Home Office has still failed to institute embarkation checks at British airports.) Together these illustrate the unhappy, almost South American combination of authoritarianism and lethargy that marked so much of the Home Office’s trajectory during Mrs May’s leadership

As well as the baffling, infamous mistreatment of Afghan interpreters who had worked with British forces in Afghanistan (for which she characteristically escaped censure), Mrs May’s tenure at the Home Office saw a number of troubling decisions about who is and isn't allowed to enter the UK on ideological and public safety grounds. Whatever one may think of the controversial American bloggers Pam Geller and Robert Spencer, neither have advocated violence, and both have spoken all around North America without incident. Their 2013 exclusion from the UK should concern anyone who takes freedom of speech seriously.

Then there was the cynical political correctness. Mrs May talked about coming down hard on hate crimes and lambasted the police about a lack of diversity. But she abjectly failed to identify the child rape rings of Rotherham, Rochdale, Sheffield, Bradford and Oxford as the racially and ethnically motivated hate crimes that they were.

When it came to police reform, May’s efforts were far less ambitious or impressive than anything achieved by Gove in the Department for Education or the Ministry of Justice. She certainly deserves credit for forcing through changes in pay, conditions and pensions and for potentially improving police leadership by allowing 'direct entry' to senior positions from civilian life. But many of the more disturbing tendencies in British policing have become worse under her leadership, most obviously the distortion of policing priorities by public relations concerns.

The nadir of this phenomenon was Operation Midland, one of the most disgraceful episodes in the history of modern British policing. Millions of pounds were spent investigating allegations that various former ministers, intelligence chiefs and other top officials had been part of a paedophile ring that raped and murdered young boys. The fact that that both Detective Superintendent Kenny McDonald, the senior officer on this case and his boss, Sir Bernard Hogan-Howe, emerged from this sinister debacle with their jobs, was rather more illustrative of Mrs May’s real attitude to the policing establishment than her famous speech to the Police Federation in 2014.

May has also done little to reverse various policing trends that have alienated the public from the police, including the abandonment of neighbourhood policing, the substitution of decoy-like PCSOs and CCTV for beat patrols, and the massaging of crime statistics, At the same time Mrs May has given the nod to massive, transformative budget cuts that may genuinely make Britain’s police forces unfit for purpose. There is an argument that smaller overall numbers and decreased budgets don’t automatically translate to fewer frontline officers or less effective policing. But this assumes that forces are well-run and that resources aren’t so depleted that they cannot function. However, if many of your 43 separate forces are poorly managed and are culturally inclined to prioritise exciting, fashionable or easy aspects of policing – such as trawling social media for hate speech – over patrolling the streets, then smaller numbers will definitely make a difference for the worse.

Thanks to the cuts and also to Mrs May’s disdainful attacks on certain aspects of police culture, she leaves the Home Office with police morale at what may be an all time low (though nowhere near as bad as in the armed forces). It is telling that many police officers believe that her loud opposition to ‘stop and search’ and criticism of inadequate police diversity have been typical May opportunism that had more to do with image-management and personal ambition than any genuine concern for minorities or civil liberties.

And what of May's record on migration? During the last election campaign David Cameron took brickbats for the fact that net migration into the UK had actually increased from 244,000 in 2010 to 330,000 in 2014 rather than being brought down to less than 100,000 as he had committed. Mrs May, the cabinet minister actually responsible for making the government’s commitment a reality, faced remarkably little criticism or even questioning about why this had failed.

The target was probably an impossible one given Britain’s chaotic border arrangements in 2010, and May certainly could not be blamed for the attractiveness of the UK and its work opportunities for young EU citizens from countries with ever-worsening youth unemployment. But you would be hard pressed to find evidence of serious and effective effort to repair or reform the parts of the Home Office entrusted with border security and migration.

As the then shadow home secretary Yvette Cooper pointed out, three years after May took over the ministry, the number of people refused entry had dropped by 50 per cent, the backlog of finding failed asylum seekers had gone up, the number of foreign prisoners removed had gone down, and the number of illegal immigrants deported had also gone down. Tens of thousands of international students kicked out of the country by the Home Office - in a panicked response to a TV documentary about a test cheating scam – then turned out to have been wrongly deported. Meanwhile, bogus colleges that falsify 'student' records so that foreigners can work illegally in the UK have continued to flourish because the Home Office has an inadequate number of staff assigned to checking them.

The Border Force, now a separate agency with spiffy new uniforms, is demoralised, overstretched and facing deeper, remarkably ill-timed austerity cuts. It has less than a handful of patrol boats to guard the coastline even as the migrant crisis deepens, and it is unable to keep any watch at all on the country’s many small airfields. Yet, remarkably, the Home Secretary never showed any inclination to stand up to the Chancellor on its behalf – even in the wake of the Paris and Brussels terrorist attacks .

Despite her carefully fostered reputation for toughness, Mrs May’s record on extremism is perhaps the least impressive aspect of her checkered tenure at the Home Office. Any public official who seriously addresses radicalisation, ghettoisation and extremism risks being labeled an Islamophobe or worse. It takes a brave politician, one more committed to doing the right thing than to securing a glorious political future, to take on this hornets' nest; Mrs May was not such a politician. This began to be clear during the Trojan Horse affair, when official reluctance to confront radicalisation in Birmingham schools prompted a concerned Education Secretary to venture onto the Home Secretary’s turf. (Her characteristic fury at this trespass was damaging to both departments at the time, and may well wreak havoc into the new government. Certainly her firing of Michael Gove’s as Justice Minister, despite the fact that his incomplete prison reforms have been universally lauded, looks like a destructive act of petty vengeance and personal spite.)

It became more apparent when Mrs May, having delivered some appropriate sound-bites, avoided potential career-inhibiting controversy by ensuring that the Home Office’s efforts to deal with tricky issues like female genital mutilation, honour killings and forced marriage remained as low key - and low impact - as possible. But it is even more obvious in the investigation Mrs May eventually set up into whether Britain’s Sharia courts, some legal, some not, might possibly discriminate against women in matters of divorce, domestic violence and child custody, as a result of a ‘misuse’ of Sharia teaching. (In the past the Home Secretary has implicitly claimed a surprising intimacy with Islamic law and political thought, asserting in 2014 that the actions of Isis 'have absolutely no basis in anything written in the Koran.')

Of course, Mrs May is hardly the first ambitious politician to have disregarded principle or even the public good in order to smooth her ride to the top. Her defenders would argue that a pragmatic lack of ideological ballast is one of the qualities she shares with David Cameron.

More disturbing are the tendencies that have caused her to be nicknamed Teflon Theresa or McCavity May. As well as the buck passing that ensured that blame for all of the Home Office’s failings fell onto junior ministers and civil servants, Mrs May and her staff put tremendous effort into ensuring that she rarely - if ever - faced a Paxman-style grilling. And so good were they at applying pressure on the media that remarkably few critical articles about her have ever been published. There’s even a peculiar tendency for those that have been published to be taken down or become unavailable.

Ronald Reagan once said there is no limit to what you can achieve if you don’t mind who gets the credit. Unfortunately it is also true that if you mind very much who gets credit and blame, then you are unlikely to achieve a great deal. As Home Secretary Theresa May was hobbled by her own ambition. Perhaps now she has the power and position she worked so hard to get, her main priority can at last be the country she serves.