Jeremy Corbyn has carried out a shake-up of the way the Labour Party operates with a review of the party’s internal structure and a reshuffle of his backroom staff.

As the leader approaches nine months in the job, Simon Fletcher, chief of staff, will move to a new role of Director of Campaigns and Planning. While some have seen this as readying the party for a possible post-referendum snap election, it is seen internally as filling a more long-term brief – covering areas such as the anti-tuition fees campaign as well as elections.

Andrew Fisher, the sometimes controversial political aide, will become the new Director of Policy, effectively replacing Neale Coleman, who stepped back from the role after January’s reshuffle.

It comes less than a month after Fletcher’s deputy Anneliese Midgley left to take up the role of Political Director at Unite, Britain’s largest trade union.

The reshuffle appears to be a sign Corbyn’s senior team believe the threat of a challenge has diminished.

Leadership sources say they believe the move around will provide a flatter structure which will make the running of the office more effective. Corbyn’s position is now considered to be more secure than it was, meaning longer term planning can begin.

This, it seems, is where Fletcher’s new role comes in. As Chief of Staff, his job was seen as putting the leader’s office together and get it working; now that task is done he can take up the new role as the focus of the leadership team shifts.

Meanwhile a review of the party’s internal structure has also been announced, headed up by former head of the home civil service Lord Kerslake. He will assess the working relationships between the leader’s office, the Shadow Cabinet and the Labour HQ at Southside.

Getting the former senior civil servant in to carry out the review is a sign that the leadership is keen to avoid accusations of a radical power-grab, and sources stress that it is usual for a review of this kind to be carried out in order to streamline how the party structures work, and how effectively the different arms of the party work together.