It was mostly a sea of green across global equities as the likelihood of another US government shutdown lessened thanks to an agreement over border security for the US-Mexico border.
At midday, the FTSE 100 was up 0.3% at 7,152.
Among the biggest risers were utility company SSE, up 1.3% at £11.89, and pharmaceutical giant AstraZeneca with a 1% rise at £57.37.
Brent crude oil gained 2% to $62.73 per barrel.
MID AND LARGE CAP RISERS AND FALLERS
Online broker Plus500 tumbled 32.4%, despite almost doubling its annual profit. The company warned tighter UK regulations would cause it to post a profit in 2019 'materially lower' than market expectations.
Travel company TUI dropped another 3% as it posted a deeper earnings loss in its fiscal first quarter, while reiterating last week's shock guidance downgrade.
Pharmaceutical company Indivior shed 2.8% after a US court denied its appeal against a decision allowing rival Dr Reddy's Laboratories to sell a generic version of its opioid addiction treatment.
Train and bus company Stagecoach advanced 1.6% as it confirmed that subsidiary East Midlands Trains agreed a new short-term rail franchise with the UK's Department for Transport.
Insurer AA added 1.4% on announcing that it expected its annual underlying earnings to be at least £340m, in line with its previous guidance range of £335m to £345m.
SMALL CAP RISERS AND FALLERS
Media consultancy Ebiquity warned 2019 profits for its consultancy business will be flat as cost pressures continued, causing the shares to fall 9.8% to 55p.
Data firm for the retail and transport sectors Touchstar rose 4.3% as it guided for a shallower loss than the market was currently expecting, due to margin improvement.
Logistics company Wincanton gained 1.5% on news that it had been selected by UK tax authorities to support air and sea freight inspections.