When Tony Hall was appointed director general in 2013, he was given the task of steadying a BBC that had been seriously rocked by its handling of the Jimmy Savile and Lord McAlpine scandals. Hall may have lasted much longer than his predecessor’s 54 days, but he leaves the BBC facing even greater existential threats.

Even for a public service broadcaster used to crisis, the combination of an unfriendly government and an ageing audience present Hall’s successor with exceptionally tough challenges.

Hall had wanted to continue as director general until the BBC’s centenary in 2022 when he would be 71, but the seeds of his decision to step down this summer were sown during the torrid negotiations to renew the BBC’s 10-year charter when he agreed to a mid-term review in 2022.

At the time Hall justified the BBC’s agreement to pay for free licence fees for the over-75s, saying the fee had been guaranteed and index-linked until the end of 2027.

But he lost a hard-fought negotiation over the government’s insistence on having a mid-term review in 2022. This failure means that the starting gun over how the BBC should be funded has already been fired. John Whittingdale, the former cabinet minister who helped negotiate the settlement, confirmed as much yesterday when he said this review would be “the beginning” of the discussion.

Given how much is at stake, Hall’s desire to hold out for the big celebratory parties was not tenable, even had there not been a job at the National Gallery on offer.

The mid-term review is likely to be used to discuss both the abolition of the £154.50 charge and also the decriminalisation of non-payment, if Boris Johnson’s thinly veiled threats since his election offer any clue. Since Christmas, the former chair of Ofcom Patricia Hodgson has called for a subscription model to be introduced.

Recognising the imminent threat, Hall said in a statement to staff: “It must be right that the BBC has one person to lead it through both stages.” His decision to allow his successor time to manage both processes was greeted as “a grown up thing to do” by one commercial rival yesterday.

The decision was also said to be encouraged by the BBC’s chair, Sir David Clementi, whose four-year term is due to expire in February 2021.

Given Hall’s insistence that the last charter review was a “strong deal”, it would be wise to take his statement that he leaves the BBC in a “much stronger place than when I joined” with a pinch of salt.

Yet he has presided over several successes both onscreen and off. Unflappable in a crisis and with a strong track record as a journalist, Hall is popular among the BBC news team. He has brought a sense of calm to an organisation despite huge changes, thousands of job cuts and screams of bias. The BBC also moved early to leave London for the regions, particularly the north.

Yet he mishandled the equal pay dispute, not appearing to realise until quite late that the government’s insistence on revealing the identities of those paid more than £100,000 a year would give ammunition not to rivals wishing to poach its overpaid and typically older white male staff, but to its legions of underpaid and fed-up female employees.

Even the government’s pressure on an independent news organisation pales into insignificance next to its failure to remain essential to younger viewers and listeners. Last year an Ofcom report found that fewer than half of Britons aged 16 to 24 watched a traditional live BBC television channel each week. What’s more, younger viewers were twice as likely to watch BBC programmes on Netflix than on the BBC’s own iPlayer service.

The same report was critical of the BBC’s insistence that impartiality meant giving both sides an equal say and urged its journalists to be more willing to directly call out lies.

Despite all this, reports from Ofcom and others still suggest that the BBC is one of the most trusted news organisations in the UK – and that means the battle ahead will be a monumental one. When he was appointed, the media commentator Steve Hewlett said Hall’s “biggest test is to secure a digital future”. Now the biggest test is to secure its future full stop.