The reputation of professional lobbyists – never particularly burnished, it’s fair to say – has gone through the wringer of late, with everyone from Boris Johnson to Greenpeace (itself active in that regard) sticking their oar in.

There is a problem, acknowledges Iain Anderson, boss of the newly supersized City lobby firm Cicero, much of which comes down to the “cloak and dagger, secret-squirrel stuff”. That problem needs to be addressed – not least because the world is “shredding” the old ways of doing things.

“Part of the perception is that it is all a bit funny-handshakes,” he says. “Part of the reason I called the firm Cicero is because I believe it’s about conversation, it’s a public policy debate.”

But Whitehall is still “fundamentally set up” to have these “conversations in the shadows”, he adds. “It’s much easier to take a City business to the European Union… there is a willingness to engage. It’s much harder here, and always has been, although the current mood makes that worse.”

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Indeed, business groups and lobbyists were all but frozen out of Number 10 ahead of last year’s election – although the door has been flung open since then.

And the inbox at Cicero which recently snapped up politics Westbourne Communications – forming a new public affairs agency with a total fee income of £7m – doesn’t stop filling up, not least with Brexit-related issues as we enter the final furlong.

Despite the wider mood, Anderson says government has become more open to discussing issues with business since the election and points to the adoption of a transition period as evidence that the City’s voice is being heard. But there are plenty of other areas – not least the dropping of mutual recognition for financial services firms – that have ruffled feathers in the City.

“We’re saying ‘you guys didn’t do any heavy lifting on it – you just dropped it’ – because firms are very perturbed,” he says. “You could almost characterise [the government’s approach] as a win on goods for Remainers and a win on services for Leavers – but it does make people very, very nervous.”

Some of that nervousness has tipped over into emergency planning, and Anderson says this autumn will see “a massive, massive push” for the Article 50 deadline to be extended. “That’s the big lobby issue starting this summer… the biggest single thing we will be working on is extending Article 50,” he says.

"There is an expectation that we’re not going to cross the line for a deal in October, although if we do you will just hear the sigh of relief in this place, because of course without that there is no transition."

Although larger firms are already beginning to execute their worst-case-scenario plans, the majority of firms have been working on the basis that the status quo will remain until December 2020. “Behind closed doors, [government] is still saying we are heading for this – but still, lobbying is very, very strong”.

Anderson also believes there is a growing push for a kind of transition 2.0, with the first phase being a standstill period in which further talks can take place to get agreements around more fiddly issues, such as financial services, followed by a genuine implementation period.

But he believes the “maximum moment of danger” for May will not come this autumn – although any failure to present a deal to MPs will be potentially fatal – but 29 March next year, when the UK is currently scheduled to leave the EU.

“If we are out, if there’s no extension [of the Article 50 departure point] that is when the [eurosceptic MPs’ collective] European Research Group and tabloids will start saying ‘now we need someone new’,” he says. That means this September’s Conservative Party conference will be a “beauty parade” of potential successors.

Although former foreign secretary Boris Johnson has emerged as a frontrunner among the party faithful, Anderson believes he has shot himself in the foot and lost the support of the City after his “f*** business” comments. “When Boris was mayor he was lining up to do stuff with business,” Anderson says. “How he has behaved since he got into government – well, the relationship between business and Boris is virtually non-existent.”

He suggests contenders such as environment secretary Michael Gove or possibly former home secretary Amber Rudd could win the backing of industry “but it’s hard to see – I find I can’t get business leaders very excited about our politicians”.

And what about after Brexit, I ask? “There is no ‘after Brexit’,” says Anderson somewhat ominously. “Everyone is turning their minds to the world after March next year, or after Theresa May. But this conversation about how we align, or don’t, with Europe is going to go on and on and on.”

Read more: Brussels could control financial services market access after Brexit