Joanna Shields is to be replaced by BlackBerry's global marketing leader Gerard Grech as CEO of Tech City UK next month.
Shields, who has been CEO and Chairperson of Tech City UK since October 2012, will remain in the unpaid Chairperson role.
The news was announced last Friday, on the same day that it was revealed that the London part of Tech City would be handed over to London & Partners from April 2014.
Tech City News reported that these "drastic changes" meant the future for the quango is looking "increasingly bleak".
London & Partners, the not-for-profit promotional organisation funded by the London Mayor's office, will take responsibility only of the London remit but stated it would "continue a close partnership with them in the next fiscal year."
"Tech City is an integral part of the London proposition and we look forward to continuing to highlight its unique strengths as we promote the whole of London across the world," a spokesperson for the firm told Tech City News.
It is believed that the Mayor's team have plans to regenerate Old Street roundabout, more commonly referred to as Silicon roundabout, after the original £50 million plans were scrapped due to technical complications.
One growing problem that will need to be addressed is the inability of many startups being able to afford the running costs of their businesses. Soaring rent prices and operational costs were highlighted as a barrier to growth by a recent survey carried out by YouGov.
According to the survey of 155 middle managers from London startups, 70 per cent of tech firms in London have found it difficult to expand due to these barriers.