A Sky executive who lent a townhouse to Boris Johnson’s leadership campaign and an academic who accused politicians of exaggerating racial prejudice were among Downing Street’s controversial first appointments on Tuesday.

Andrew Griffith, the chief financial officer and chief operating officer at the pay-TV group, has been appointed as the chief business adviser to Number 10.

He will work closely with the new prime minister who reputedly said “fuck business” when confronted with companies’ concerns over Brexit.

Munira Mirza, who was a deputy mayor for Johnson throughout his time at City Hall, has been recruited to be head of Number 10’s policy unit, Tory sources said.

She was a prominent critic of Theresa May’s racial disparities audit for public services, saying the “scene was being set for another bout of political self-flagellation regarding the subject of race in Britain”.

Quick Guide Boris Johnson's to-do list Show A cabinet reshuffle The first task of any new PM involves rewarding some loyal allies and disappointing more. Several Johnson loyalists have had their eye on the post of chancellor, but only one can do it. A complete clearout of May’s remain-minded ministers provided plenty of opportunity to reward the Brexit believers though. Brexit The issue that will define a Johnson premiership. He has promised to rapidly renegotiate almost all of May’s departure deal, ditching the Irish backstop border guarantee policy – something that would seem a huge task over any timescale, let alone little more than 12 weeks, a fair proportion of which is taken up by a summer break. If this fails, he will be set on a no-deal departure for 31 October, and a likely huge clash with MPs. Iran If Brexit wasn’t enough, a new Johnson government must immediately take steps to make sure he doesn’t begin his time in No 10 with a slide into war. The situation in the gulf is complex, fast-moving and hugely dangerous. Johnson did not cover himself in glory as foreign secretary, especially over Iran. It will be his task to prove he has learned. Managing parliament and Tory MPs Johnson will start as PM with a working Commons majority of four, thanks to the DUP, but within weeks it is likely to be down to three if as expected the Liberal Democrats win in the Brecon and Radnorshire byelection. If this wasn’t tricky enough, a small but significant section of Tory MPs openly detest Johnson, and will not want to help him out - and with his cabinet sackings, the ‘Gaukward squad’ of former senior cabinet members set on blocking a no-deal Brexit swelled in ranks. Loosening the purse strings Such was the fiscal largesse on display from both Johnson and Jeremy Hunt during the hustings process that much as he will seek to kick any decisions towards an autumn budget, voters – especially Tory members – will be expecting both tax cuts and more spending on areas such as education and the police. Everything non-Brexit This might sound glib, but there is a lot to consider – during the three-plus years of Brexit introversion May’s government failed to properly grasp any of a series of long-term, pressing national problems: the crisis in social care; the future of the NHS; a climate emergency; the increasingly insecure future of work; a broken housing market; rampant poverty, including among many working people. This is a huge workload for any new administration. Being prime ministerial Critics might say this is Johnson’s single biggest challenge. The leadership process has shown that while he endlessly harked back to supposed successes as London mayor – an often ceremonial role with relatively few powers – Johnson was notably quieter about his period as foreign secretary. Being prime minister is like the latter, to a factor of 10 – a never-ending succession of red boxes containing vital documents, of urgent briefings, of a whole system hanging on your decisions. Johnson has a tendency to ignore advice, pluck statistics out of the air and rely on sudden, cheap glibness. Curbing these long habits will be a daily struggle - his adopting the acronym 'Dude' in his victory speech shows just how hard it is for him. Peter Walker Political correspondent

The disclosures followed a frenetic day of rumours over who would be chosen by Johnson to advise the new Tory administration following his victory over Jeremy Hunt.

Griffith’s role will be to help Johnson rebuild ties with the business world amid fears that the new Conservative leader is happy to embrace a no-deal Brexit if he cannot come to an agreement with the EU before the 31 October deadline.

He will be based full-time in 10 Downing Street from Wednesday, the first day of Johnson’s premiership, Sky’s chief executive, Jeremy Darroch, said in an email to staff.

Griffith is expected to stand down from Sky while working for Johnson. The former Rothschild investment banker joined Sky in 1999, and became finance chief for the group in 2008.

He was a key part of the team during the attempted takeover of Sky by Rupert Murdoch’s 21st Century Fox, when Murdoch’s son James was chairman of the broadcaster.

Johnson, who is expected to enter No 10 next week, has been spending up to 13 hours a day at Griffith’s lavish £9.5m townhouse, with sources on his team saying he has switched his focus towards strategy for government.

A Johnson campaign source said Griffith had kindly opened up his home to let members of the transition team meet there, but the businessman was not part of that operation.

Griffith received about £17m after Sky was acquired by Comcast, which needed to buy out some of the stakes and share schemes held by Griffith and other staff in the group.

He ran as a Tory parliamentary candidate for Corby in 2001 and 2005. He lost both times to Labour.

Munira Mirza during her time as Johnson’s deputy mayor for education and culture. Photograph: Mary Turner/Getty Images

Mirza, whose family came to the UK from Pakistan, criticised the Labour MP David Lammy’s 2017 review of racism in the criminal justice system, which was commissioned by David Cameron and supported by May.

She said it was an example of how “astonishingly, it seems that a lot of people in politics think it’s a good idea to exaggerate the problem of racism”.

She disputed his view, and that of May, that the criminal justice system treats black people more harshly than white people, arguing that social and economic reasons lie behind the higher proportions of BAME people in prison – not institutional racism.

Mirza wrote: “Paradoxically, just at the point when racist attitudes were declining in society and many ethnic groups were integrating successfully, our political leaders became obsessed with racism … The tragedy is that accusations of institutional racism — and their official endorsement — have corroded BAME communities’ trust in public services, thereby making things worse.”

Last summer, Mirza defended Johnson’s controversial article that likened women in burqas to letterboxes and has been a long-term critic of multiculturalism as a policy choice.

“There are many people in this country who are uncomfortable about the burqa. When people argue we should use more sensitive language what they are really saying is let’s not be critical at all, let’s not offend, let’s not criticise this practice because it upsets Muslims,” she said.

Mark Spencer, the 49-year-old MP for Sherwood, will become Johnson’s chief whip. This is a key position as the new premier attempts to govern with a working Tory-DUP majority of just two.

His appointment was praised by MPs across the party. Long-serving Conservative Sir Nicholas Soames said he was a “really excellent sane and wise choice”. The business minister Andrew Stephenson said: “Congratulations to the new chief whip - the man who taught me how to ‘put a bit of stick about’.”

Meanwhile, a former ambassador to Denmark and Foreign Office official is being tipped as Johnson’s new Brexit negotiator.

David Frost is a career diplomat and was head of Europe at the Foreign and Commonwealth office and and a former special adviser to Boris Johnson when he was foreign secretary.

He is currently chief executive of the London Chamber of Commerce and Industry but has years of experience working with the EU.

“He believes there is a deal to be done and will pursue that,” said one source who knows Frost.

However there are also concerns, if his appointment is confirmed, that the key “sherpa” role is going to someone who is not a full-time member of the civil service.

“David is good, he knows Europe inside out, but Johnson will need someone at a senior level in the civil service who will be in charge of the day-to-day work,” said the source.