Today is a day for goodbyes in Downing Street. The swift transformation from incumbent Prime Minister to the arrival of the delivery van to last farewells from the steps of No.10 is one of our most distinctive and extraordinary political conventions. But it has never been more brutally on display than over the past few days. Three weeks ago David Cameron was planning his government’s post-referendum relaunch. Two days ago he was planning a summer of legacy moments before he stepped down in September. Today he will awake to a No.10 flat full of cardboard boxes and post-it notes for the movers. He will also get out of bed accompanied by the thought that, from tomorrow, he will no longer be at the centre of things – a thought that will fill him with a mixture of emptiness and delight.

The day of leaving Downing Street is full of drama, process and farce. On May 11, 2010 I experienced one of my own. It was Gordon Brown’s final day as Prime Minister, the fifth day of coalition negotiations that followed the 2010 election. The prospects of Labour staying in power after the election producing a hung Parliament had always been low. But from mid-morning onwards on Tuesday May 11, it became clear to us that it would be our last.

It became a day of reminiscences. Without anyone deciding, we started talking about moments from the past with Gordon – ludicrous moments, momentous moments, moments we botched, moments we got right. We cried with laughter at some of the funnier moments, but we cried together. The intimacy that comes from working in a team for so long where the scrutiny is constant, the stakes so high and the atmosphere so charged is difficult to describe. Making yourself cry with laughter is a convenient way of hiding the tears that come from the loss that you know awaits.

In between the reminiscences we stood around watching the rolling news coverage – watching the world watching us. Journalists constantly texted us asking for any nugget of information about what was happening inside No.10, no matter how mundane, to give them a bit of colour. I half-expected Sky to run a banner saying “Breaking News: Gordon Brown unpeels his 5th banana of the day”.

The tenure of our Prime Ministers is bookended by two letters. The first is one with instructions to those in charge of our nuclear weapons, written as soon as they arrive in Downing Street; the last is one with good wishes for your successor written just as they leave. Gordon wrote three letters in those final hours – two to heroes that inspired him (Aung San Suu Kyi and Nelson Mandela) and one to David Cameron (accompanied by a bottle of something strong, as I remember). For all their rivalry, his letter to Cameron was warm and sincere, encouraging him never to forget what a privilege it is to be our nation’s leader, and full of praise for the extraordinary professionalism of the staff at Downing Street.

Around us, I was aware that the Downing Street civil servants kept furtively slipping out of the office, meeting to organise the logistics of the transition later that day. I said dozens of goodbyes that day to them, and by the end they were as tearful as us. And only then did I realise something from three years before. In May 2007, when Gordon Brown took over from Tony Blair, I was struck by how red-eyed the Downing Street staff had been when we arrived. I thought at the time it was their fear of the prospect of Team Brown at No.10. But I realised, when I said my own goodbyes to them three years later that it was because they had just said goodbyes of their own to Team Blair, with whom they had worked for over a decade.

The last hour or two was tough. I never realised how complex it could be to organise the choreography of a group of people leaving a building. The sequencing was discussed and re-discussed. Gordon, flanked by his family, gave a short speech to us all. Eventually we lined up outside no.11 Downing Street to see Gordon and his family say goodbye from outside No.10. Then we slipped back in to say our very final goodbyes to the Downing Street team. But they were already hard at work preparing for their next boss. Conscious that Operation “The King is Dead, Long Live the King” was underway, I half-sprinted out the front door, and went to the pub.

Working at No.10 whatever the weather (and boy did we have some storms in our time) is a privilege beyond compare. I used to literally pinch myself walking past the tourists through the Downing Street gates every morning, to remind myself how transitory it was, how much responsibility even a lowly aide like me had, and most of all never to take it for granted. When the music stops, it takes a chunk out of you, and you lose your bearings for a short time. I hope David Cameron and his team recover theirs quickly. I hope they remember the extraordinary honour it is to serve your country. And I hope they learn to cherish the freedom that comes from leaving No.10 and returning to the ranks of those they used to govern.

Lord Wood of Anfield is a Labour peer and former advisor to Gordon Brown. This article was first posted on by Lord Wood on Medium.