That immediate market reaction could just be speculative, but I doubt that. The fundamental uncertainty will flow through into a significant decline in investment, which will lead to recession, inevitably.
The decline in the value of sterling should logically lead to an interest rate rise but that would tip many UK households, and in turn many UK banks into financial crisis. Preventing this will require massive injection of funding from the Bank of England but not for investment, but just to keep banks afloat.
At the same time tax yields will fall, inevitably. Balanced budgets are now animpossibility.
Pound falls. This makes British assets cheaper. It also delivers a large dose of stimulus to the domestic economy. As in, you know, 1993?
This thus causes less foreign investment and a recession?