The FTSE 100 was up 0.7% to 7,540.59 by midday on Wednesday after strong trading in Asia and the US overnight.
The global mood had been lifted by testimony from US Federal Reserve chair Jerome Powell, who reassured investors by saying the US central bank wasn't afraid to raise rates to ease inflation.
Supermarket giant Sainsbury's rose 2.8% to 287.2p, having upgraded its annual profit guidance despite its total sales slipping 0.1% in the third quarter.
Sainsbury's said it now expected to report an underlying pre-tax profit for the year through March of at least £720 million.
Sportswear retailer JD Sports Fashion dipped 0.2% to 218.4p as it, too, forecast a full-year earnings beat after enjoying bumper sales over Christmas period.
JD Sports was now forecasting a headline pre-tax profit of at least £875 million, ahead of market expectations averaging £810 million.
Premier Inn hotels owner Whitbread gained 0.8% to £32.26 on announcing that it still expected its revenue per room rates in the UK to recover to pre-Covid levels in 2022.
Whitbread's sales in the three months through December, including from properties in the UK and Germany, rose 5.0% year-on-year, with higher accommodation sales offset by an 10% drop in food and beverage sales.
Homeware retailer Dunelm rallied 5.3% to £14.11 as it upgraded its annual profit outlook on the back of higher digital sales and fatter margins in the first half.
Dunelm's annual pre-tax profit was now expected to be 'materially ahead' of market expectations of £181 million.
Estate agent Savills climbed 7.2% to £14.15 with especially rosy guidance of an annual profit 'very significantly' ahead of the upper end of its previous range of expectations.
Savills said that since its last trading update in November, it had experienced an extraordinarily strong final trading period, particularly in the UK and Asia Pacific regions.
Customer review platform Trustpilot rose 4.2% to 290.4p on guiding for a 29% rise in annual revenue, beating its expectations.
Trustpilot's revenue for the year through December was seen jumping to $131 million, up from $102 million year-on-year, with growth on a constant currency basis of 24%.
Building materials distributor Grafton was also in on the upgrades, firming 3.8% to £12.27 after it said it expected annual adjusted operating profit within the top end of expectations.
Market expectations for Grafton's adjusted operating profit averaged £270.4 million with a range of £266.7 million to £276.3 million, the company said.
Recruitment company PageGroup added 1.0% to 640p, having nudged up its annual profit guidance after it boosted its fourth-quarter net fee income by 49%.
Operating profit for the year through December was now expected to be 'marginally in excess' of previous guidance of in the region of £165 million.
House builder Vistry eased back 0.3% to £11.5945 even as it said its annual profit would more than double, in line with previous guidance, after construction markets rebounded following an easing of lockdowns.
Looking forward, Vistry said it expected to 'deliver a significant step up in profits and returns' in 2022.
Flooring retailer Topps Tiles slipped 5.6% to 60.45p as it achieved a modest rise in first-quarter like-for-like sales, but warned supply chain pressures would hurt its margins.
Like-for-like sales at Topps Tiles's main retail business in the three months through December rose 1% year-on-year, though were up 21% on a two-year basis, the company said.