Sterling slipped further and Irish shares fell sharply as fears of investors rose that the political turmoil in the UK will lead to Boris Johnson becoming leader, and Britain crashing out of the EU without a deal.

A record-breaking rally in US stocks paused yesterday as investors assessed whether the rise in stock valuations overstated the recent improvement in the economy.

Wall Street closed an erratic session mixed today after an uneven batch of earnings reports made investors more cautious about buying stocks.