Sterling's strength appears to be mostly a function of USD weakness - BBH

"Prime Minister May's troubled cabinet shuffle did appear to shift power between the hard and soft Brexit factions," BBH analysts argue.

Key quotes

Sterling's strength had appeared to be mostly a function of the dollar's weakness, but the gains were bolstered by reports that the Spanish and Dutch finance ministers were endorsing more generous terms of negotiations.   

This too was exaggerated.  Since the UK's referendum in mid-2016, the other EU countries have shown a united front.  Neither Spain nor the Netherlands is defecting.  Of course, the EU wants a deal that keeps the UK as close as possible to the EU.  Moreover, we note that Spain's de Guindos is thought to be a leading candidate to replace Constancio as vice president of the ECB in June.  

On the other hand, the prospect of a second referendum, which has been talked about almost since the last referendum that had been decided by a tight 52-48 margin may be increasing.  Some recent polls have suggested that the Remain camp would win if another referendum was held.