Strong gains for BP, Whitbread and financials stocks ensured that the FTSE 100 was firmly in positive territory on Tuesday morning as traders showed optimism ahead of central-bank meetings later this week.Sentiment across Europe was lifted early on after Swiss banking giant UBS smashed profit expectations in the first quarter and German lender Deutsche Bank rose after saying it would raise up to $6.3bn in new capital.London's benchmark index has now risen by around 3.0% since the start of last week after a raft of disappointing indicators from the Eurozone sparked hopes that the European Central Bank (ECB) will move to ease monetary policy when it meets on Thursday. The consensus is expecting at least a 25 basis-point reduction in the ECB's key lending rate from the current record-low level of 0.75%Shavaz Dhalla, a Financial Trader at Spreadex, said this morning: "The optimism seems to be well grounded as the Eurozone is struggling with returning to growth and recent data showing poor confidence levels by businesses is also concerning investors. Evidently investors now believe that more will be done by officials to help the struggling economy."Meanwhile, the US Federal Reserve is convening today for a two-day meeting and is widely expected to leave its current stimulus measures unchanged given last week's disappointing growth figures. It was revealed on Friday that first-quarter gross domestic product in the States expanded by just 2.5%, short of the 3.0% forecast.FTSE 100: BP impresses as first-quarter profits soarOil major BP was a high riser after replacement cost profits jumped from $4.8bn to $16.6bn in the first quarter, helped by proceeds from the disposal of its interest in the TNK-BP joint venture.Costa owner Whitbread was higher after recording a double-digit increase in annual revenue, profit and the dividend despite adverse weather conditions.Asset manager Aberdeen was performing well, extending gains after yesterday reporting a 13% increase in assets under management in the first half. The stock was given an extra lift this morning after JPMorgan Cazenove, Bank of America Merrill Lynch and Morgan Stanley all raised their target prices.Other financials, including Lloyds, RBS and Schroders were also making gains early on.Tobacco giant Imperial was in demand despite seeing revenues and profits slump in the first half due to weakness in Europe, excise-driven market dynamics in Russia and a new pricing strategy in the US.FTSE 100 - RisersLloyds Banking Group (LLOY) 55.60p +3.93%Evraz (EVR) 163.70p +3.35%BP (BP.) 470.35p +2.98%Royal Bank of Scotland Group (RBS) 301.50p +2.55%Schroders (SDR) 2,376.00p +1.63%Hammerson (HMSO) 531.00p +0.95%Serco Group (SRP) 620.00p +0.90%Shire Plc (SHP) 2,033.00p +0.79%ARM Holdings (ARM) 986.50p +0.77%Weir Group (WEIR) 2,240.00p +0.72%FTSE 100 - FallersCentrica (CNA) 371.40p -2.16%Tullow Oil (TLW) 999.00p -2.15%Wood Group (John) (WG.) 785.50p -1.44%Unilever (ULVR) 2,768.00p -1.32%International Consolidated Airlines Group SA (CDI) (IAG) 271.10p -1.27%Standard Life (SL.) 381.40p -1.06%Antofagasta (ANTO) 901.50p -0.93%Reed Elsevier (REL) 754.50p -0.92%Anglo American (AAL) 1,596.50p -0.78%BG Group (BG.) 1,074.50p -0.78%FTSE 250 - RisersInvensys (ISYS) 381.00p +4.44%Capital & Counties Properties (CAPC) 314.10p +3.08%New World Resources A Shares (NWR) 158.40p +2.92%Carpetright (CPR) 648.57p +2.78%Ocado Group (OCDO) 171.20p +2.39%Afren (AFR) 129.70p +2.05%Alent (ALNT) 337.40p +1.96%Synthomer (SYNT) 200.40p +1.93%Chemring Group (CHG) 281.40p +1.77%Man Group (EMG) 104.90p +1.75%FTSE 250 - FallersNMC Health (NMC) 325.00p -3.79%Heritage Oil (HOIL) 163.90p -3.70%Lonmin (LMI) 277.70p -2.66%Genus (GNS) 1,371.00p -1.93%Big Yellow Group (BYG) 400.60p -1.79%Thomas Cook Group (TCG) 128.30p -1.69%Hochschild Mining (HOC) 258.70p -1.64%United Drug (UDG) 304.70p -1.30%Balfour Beatty (BBY) 220.30p -1.17%Centamin (DI) (CEY) 41.30p -1.08%BC