- Leaders to take 'all necessary policy measures'- Whitbread provides a lift on the Footsie after strong Q1- Greece, Spain and FOMC in focusThe FTSE 100 index advanced in early trading on Tuesday morning after euro members pledged to 'safeguard' the region.According to a leaked draft communique, Eurozone leaders of the Group of 20 said that they "will take all necessary policy measures to safeguard the integrity and stability of the area, improve financial markets and break the feedback loop between sovereigns and banks."Meanwhile, Standard & Poor's has assured that the sovereign credit rating and outlook on Greece (CCC/stable) have not been affected by the outcome of the elections. The credit ratings agency expects the parties to reach an agreement to "modify Greece's current programme of external financial support from the Troika (European Commission, International Monetary Fund and the European Central Bank)". Investors will continue to keep a close eye on Spain ahead of results of the independent audit of the country's banking system on Thursday. Spanish 10-year bond yields eased this morning, but still remain in 'unsustainable' territory; the rate was 2.6 basis points lower at 7.132%.In other news, the Federal Open Market Committee comes together today for a two-day meeting; markets are hoping that members will vote on further easing measures in light of recent economic data and Eurozone concerns.FTSE 100: Whitbread surges after first-quarter resultsForecast-beating like-for-like (LFL) sales growth in its first quarter saw shares of Whitbread jump early on. The Premier Inn and Costa Coffee owner reported that LFL sales increased by 4.5%, better than expectations of a 3% improvement.Engineering group Weir was also making impressive gains after reiterating its full-year forecast at its capital markets presentation today. Jefferies has said that this implies the reconfirmation of the pre-tax profit guidance of £470m "which would in theory be equivalent to a 4% upgrade versus Bloomberg consensus forecasts".Property firm Hammerson rose after announcing that it is set to off-load most of its London office space as it pushes forward with plans to focus solely on retail space. The company has exchanged contracts on the majority of its office portfolio with Brookfield Office Properties for £518m. Consumer products groups Unilever and Reckitt Benckiser and supermarket giants Sainsbury's and Morrison were out of favour after France's Danone slashed its 2012 guidance on the back of the tough trading environment in Europe in the second quarter.FTSE 250: Home Retail rockets early onShares in Home Retail soared after the sales decline at its Argos division slowed slightly in the first quarter. The group did reveal however, that the severe wet weather has hurt sales at its DIY and garden business Homebase. Fellow retailer Dixons was on the up after Bank of America upgraded the stock to neutral.Engineering and construction group Kentz rose strongly after it said it was on track to hit its revised targets as its backlog of work continued to grow.At the end of May 2012 that backlog had grown to $2.5bn, up from $2.46bn in April. Military counter-measures specialist Chemring was a heavy faller after saying that global defence markets continue to be uncertain, with budget cuts in all NATO countries. Nevertheless, it remains confident of a strong second half and meeting full-year expectations.FTSE 100 - RisersWhitbread (WTB) 1,979.00p +7.03%Weir Group (WEIR) 1,502.00p +4.52%Kingfisher (KGF) 279.00p +2.09%ARM Holdings (ARM) 500.50p +2.02%Hammerson (HMSO) 425.90p +1.96%InterContinental Hotels Group (IHG) 1,520.00p +1.88%Antofagasta (ANTO) 1,093.00p +1.86%Tullow Oil (TLW) 1,479.00p +1.72%Petrofac Ltd. (PFC) 1,512.00p +1.68%Marks & Spencer Group (MKS) 331.30p +1.63%FTSE 100 - FallersUnilever (ULVR) 2,041.00p -2.20%Diageo (DGE) 1,572.00p -1.87%Reckitt Benckiser Group (RB.) 3,339.00p -1.48%Royal Bank of Scotland Group (RBS) 232.40p -1.23%Tate & Lyle (TATE) 639.50p -1.08%Aviva (AV.) 258.30p -0.84%Barclays (BARC) 194.50p -0.79%Lloyds Banking Group (LLOY) 29.93p -0.75%Smith & Nephew (SN.) 601.50p -0.66%Experian (EXPN) 927.50p -0.64%FTSE 250 - RisersHome Retail Group (HOME) 86.50p +16.34%Kentz Corporation Ltd. (KENZ) 348.00p +7.08%Dixons Retail (DXNS) 14.40p +5.88%Stobart Group Ltd. (STOB) 123.40p +5.02%Brown (N.) Group (BWNG) 253.20p +3.35%Genus (GNS) 1,165.00p +3.01%TalkTalk Telecom Group (TALK) 172.80p +2.73%UBM (UBM) 559.50p +2.29%SEGRO (SGRO) 218.00p +2.01%ITE Group (ITE) 189.40p +1.88%FTSE 250 - FallersChemring Group (CHG) 301.70p -6.71%NMC Health (NMC) 196.00p -3.21%Man Group (EMG) 72.75p -2.22%Ferrexpo (FXPO) 206.10p -1.81%Britvic (BVIC) 310.90p -1.68%Henderson Group (HGG) 100.60p -1.37%Bank of Georgia Holdings (BGEO) 995.00p -1.29%Smith (DS) (SMDS) 138.80p -1.07%Genesis Emerging Markets Fund Ltd. (GSS) 458.30p -0.97%Travis Perkins (TPK) 930.50p -0.91%BC