Clarity on the Brexit timetable from Prime Minister Theresa May sent the pound tumbling 0.8% against the dollar to $1.28, which overshadowed expectations that Chancellor Phillip Hammond will unveil a £5 billion housebuilding stimulus package at the Conservative Party conference.
The FTSE 100 gained 1.2% to 6,982, boosted by the impact of the weaker pound on overseas earners and by both Royal Dutch Shell stocks (RDSA and RDSB), which jumped more than 2.5% in response to higher oil prices.
West Texas Intermediate (WTI) crude oil advanced 1% to $48.37 and Brent crude oil surpassed $50 per barrel.
Gold and copper were stable at $1,313 per ounce and $4,850 per tonne, respectively.
The FTSE 250 advanced 1.2% after the UK Purchasing Managers' Index (PMI) reported its highest levels in September since 2014, as a result of growth in output, new orders and employment.
The UK manufacturing PMI index was 55.4, which was ahead of expectations and the 53.3 posted in August.
MID CAP RISERS AND FALLERS
Fund manager Henderson Global Investors (HGG) climbed 13.2% to 262.5p on news of a merger with US financial group Janus Capital, which will result in the combined group trading on the New York and Australian stock exchanges.
Aberdeen Asset Management (ADN) gained 4.6% and Jupiter Fund Management (JUP) rose 4.9% following the news as M&A chatter lifted the investment industry.
Global medical products group ConvaTec said it will float on the London stock market in late October or early November. It said it wants to raise $1.8 billion to help pay down debt.
Jefferies International recommended 'buy' for Virgin Media (VM.) with a price target of 400p, causing the broadband provider to trade 4.2% higher at 324.3p.
SMALL CAP RISERS AND FALLERS
Investors were pleased with Tethys Petroleum's (TPL) announcement that the Almaty City Court's Board of Appeals found in favour of Tethys by dismissing the appeal of the claimant and upholding an earlier decision in August to lift the seizure order over the company's assets.
St Peter Port Capital (SPPC) commenced a review of strategic option for the company, which may include a potential sale of the firm. Shares in the company traded 22.4% to 15p.
Full scale zinc production started at Vast Resources' (VAST) Manaila polymetallic mine in Romania, providing the company with a second revenue stream, which triggering a share price rise of 9% to 0.3p.
Stratmin Global Resources (STGR) jumped 15.4% on news that some existing and former directors will buy new shares at 2.5p each, which is 54% higher than last Friday's mid-market price, providing the company with £344,500 in new cash.
Interserve (IRV) won a £7.5m three year cleaning contract with blue chip energy supplier SSE (SSE).
Financial administration group Sanne (SNN) nudged higher on news it will buy American rival FAS for $52.6m, giving it a base from which to target the US market.
Exhibitions and conferences provider ITE (ITE) fell into negative territory following a downbeat trading update, which revealed a continuation of difficult market conditions.
Antiques dealer Stanley Gibbons (SGI) slumped 10.6% to 11.63p on disappointing full year results showing a swing into the red and a suspension of the dividend. Chairman Harry Wilson reported a 43% reduction in net assets due to restating prior years' results and writing down the value of its acquisition Noble Investments and capitalised IT costs concerning the development of online platform The Marketplace.
Kodal Minerals (KOD) undertook a heavily-discounted placing by issuing new stock at 0.1p each to raise £750,000 to advance its lithium exploration project.
Flooring industry consolidator Victoria (VCP) rose 5.8% to 346p following the £13 million acquisition of UK underlay manufacturer Ezi Floor.