London’s main share index opened higher as the market recovered some of the ground lost in the past two days.
Global markets have dropped sharply since Wednesday, with uncertainty surrounding the Trump presidency being blamed for the sell-off.
The row over the firing of FBI director James Comey has led to growing scepticism about Mr Trump’s ability to deliver tax and regulatory reform.
But in early trade on Friday, the FTSE 100 rose 30.10 points to 7,466.52.
Airlines shares were in favour, with British Airways owner IAG up 1.6% and EasyJet rising 1.5%.
But shares in Hikma Pharmaceuticals dropped 4.8% after the company cut its full-year revenue forecast.
Last week, Hikma had said that its launch of a generic asthma drug would be delayed after its approval was blocked by US regulators.
On the currency markets, the pound was back below the $1.30 mark. On Thursday, it had jumped above this level to the highest point since September after the release of stronger-than-expected retail sales figures.
However, on Friday it was trading at $1.2981. Against the euro, the pound was down slightly at 1.1648 euros.