FTSE100 closed positively but just 15 points ahead as traders considered Greece and were buoyed by news on a nuclear breakthrough from Iran.
The UK benchmark closed out around 16 points to the good at 6,753, with Sky (LON:SKY) the biggest gainer - up 4.08% to 1,122p.
It came as heavy weight broker Deutsche lifted the price target on the stock to 1,500p from 1,000p previously.
Iran and six major world powers have reached a nuclear deal on Tuesday, curbing the country's programme.
Alastair McCaig, at IG index, said: "We were never likely to see everyone welcoming the Iranians back with open arms but the progress made in the nuclear discussions in Vienna has been broadly seen as the pick-me-up that global markets were desperately needing."
In Greece, Alexis Tsipras is trying to get the harsh austerity measures he came back with from Brussels approved by Parliament to secure the next bailout package.
"How much fight is left in the Greeks will be demonstrated by how easily these newer, harsher terms are approved by its parliament," said McCaig.
"As the queues grow at supermarkets struggling with supplies, and more empty shelves appear in both hospitals and pharmacies, it looks more likely that humanitarian aid will reach the streets long before the European Central Bank's ELA funds are allowed to flow back into the banks again."
There has been talk that Tsipras may resign if he fails to garner enough support to push the package through, although it is thought it would pass thanks to opposition backing.
Back to Blighty and Bank of England chief Mark Carney weighed into the Greek debate by saying there were 'big execution risks' involved in the rescue deal.
Upbeat UK retail sales figures failed to lift the mood. The spectre of deflation also raised its head with UK inflation slipping back to zero in June.
Back in UK equities, FirstGroup (LON:FGP) chugged 0.5% lower to 118.5p as it forecast lower rail earnings following the end of UK franchise contracts.
Dairy Crest (LON:DCG) melted 0.8% to 561.5p as it said results from its cheese and spread businesses would be weighted towards the second half.
Elsewhere, support service group Carillion (LON:CLLN) advanced 0.71% to 354.2p after first-half revenue rose and it won an £80mln contract from BP (LON:BP.).
Drugs giant AstraZeneca (LON:AZN) added 0.32% to 4,354.2p after getting US regulatory approval for a lung cancer treatment.
Elsewhere, iodine manufacturer Iofina (LON:IOF) lifted 9.41% to 23.25p on news of a strong first-half performance and a record second quarter for crystalline iodine production.
Summit Therapeutics (LON:SUMM), which is working on muscular dystrophy treatments, was unchanged at 154p as it reported encouraging test data yesterday and held its AGM today.
Regional newspaper publisher Johnston Press (LON:JPR) backtracked around 20% to 113.5p as it reported an advertising slowdown in the run-up to the UK general election.
A notable riser was Cloudtag (LON:CTAG), which gained 20% to stand at 2.35p.