LONDON BRIEFING:SIR MERVYN King, who today delivers the Bank of England's quarterly Inflation Report, still has more than a year to serve as governor of the Old Lady of Threadneedle Street, but already there is feverish speculation on his successor.

The post is the most powerful non-elected job in the UK, and will be enhanced next year when the bank takes on sweeping new powers over the financial system. King’s 10-year reign will come to an end in June next year but an announcement on his replacement is expected this year.

There is a lengthy list of potential successors, although deputy governor Paul Tucker is regarded as frontrunner. Others include Gus O’Donnell, the former cabinet secretary, and Sir John Vickers, head of the independent banking commission. One controversial possibility is the Goldman Sachs economist Jim O’Neill and there has also been a flurry of speculation regarding an overseas candidate, with Bank of Canada governor Mark Carney strongly tipped by some.

Today, though, it’s King who’ll be in the spotlight, as he delivers new growth and inflation forecasts. The governor presents the bank’s inflation reports personally, and the quarterly bulletins provide a rare opportunity for the rest of us to observe him in action – and for journalists to ask questions – as they are accompanied by televised press conferences.

The governor could be forgiven if he’s a little nervous ahead of today’s press grilling – and not simply because the bank is finding it hard to meet inflation forecasts. King has received unprecedented criticism in recent weeks for his performance during and in the run-up to the financial crisis, and for his failure to hold an internal inquiry into what went wrong.

His high-profile Today programme lecture on the BBC at the start of the month sparked some vitriolic reaction. In the lecture King admitted that the Bank of England should have “shouted from the rooftops that a system had been built in which banks were too important to fail”. But he didn’t accept responsibility for failing to see the crisis coming.

One of the governor’s fiercest critics, economist Danny Blanchflower, was scathing in his response. “Stop the excuses,” he said. “We pay the governor a large salary to have some foresight . . . Is nobody going to take responsibility for the biggest macroeconomic mistake for a century?”

The economist, who served on the MPC between 2006 and 2009, clashed repeatedly with King over policy and has branded the governor a “cruel tyrant”.

But the most vicious criticism of the governor was contained in an article earlier this month in the Financial Times – “The Court of King Mervyn” – by the paper’s economics editor, Chris Giles. The near-5,000 word piece is a devastating dissection of King’s reign at the bank, where he is said to cut an increasingly isolated and aloof figure, hiding away in his palatial offices, attended by flunkies in pink tailcoats.

Giles interviewed 21 current and former officials of the bank for his article, although King declined the opportunity to take part. The FT writer portrays King as a disdainful and autocratic leader, whose staff are scared of him and any who challenge him risk seeing their careers sidelined.

The bank has two core purposes: keeping inflation under control and ensuring the stability of the financial system. Yet financial stability appears not to interest King – the bank publishes just two financial stability reports a year and, unlike the inflation report, King does not present them. Giles also says King rarely attended monthly financial stability meetings held in the bank; one of the few times he did, he fell asleep.

He says that when the crisis struck in 2007 “Sir Mervyn was unable to take decisions, got flustered, lost control and was not a man for a crisis.”

It’s against this background that King faces the press today, as he releases the bank’s latest Inflation Report amid signs that the cost of living is proving harder to control than expected.

The bank insisted that inflation would come down steadily this year after reaching a peak of 5.2 per cent last September but in March it showed a surprise rise from 3.4 per cent to 3.5 per cent.

Fiona Walsh writes for the Guardian newspaper in London