The scenarios assessed range from leaving the single market, the customs union, leaving both together and failing to get a transition deal, described by the study as "hard Brexit".
Sadiq Khan accused the British Government of a "total lack of preparation" on the consequences of Brexit, calling on it to change its negotiation position and agree to keep the country in the single market and customs union.
Tej Parikh, senior economist at the Institute of Directors, said: "The assessments largely echo what we already know, namely that London's professional, financial, and creative industries are deeply linked to the EU Single Market. A "no deal" hard Brexit is still a very real risk - the worst possible scenarios".
If the Government continue to mishandle the negotiations we could be heading for a lost decade of lower growth and lower employment.
It says that the effects of leaving the Single Market and the Customs Union would be "noticeably more severe for the rest of the United Kingdom than for London, which implies that the rest of the United Kingdom will be much worse off than London following Brexit".
He added: 'The analysis concludes that the harder the Brexit we end up with, the bigger the potential impact on jobs, growth and living standards. The paper is a response to the government's failure to produce its assessment on how Brexit would impact the economy.
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Mr Khan is warning that with just 10 months to go, time is running out.
Some Cabinet ministers involved in the Leave campaign are known to dismiss such studies as "Project Fear".
While many MPs and politicians across the political spectrum oppose the move, ministers have committed to leaving the EU's single market and customs union saying that to do otherwise would prevent them from controlling immigration, seen as a major driver of the Leave vote.
Over 480,000 jobs could be lost nationwide by the year of 2030 as well as 50 billion pounds ($67 billion) of foreign investment in the event of the so-called hard Brexit, in which no transition period takes place, the newspaper noted.
The calculations are in line with assessments done before the referendum by the International Monetary Fund and the National institute of Economic and Social Research.
A study commissioned by London Mayor Sadiq Khan shows that nearly half a million jobs are under threat if Britain fails to strike a deal on future relations with the European Union before it leaves the bloc.