Plant hire group Ashtead has raised full-year guidance after a strong first quarter performance.Underlying revenue was up 12%, or 21% on a constant exchange rates (CER) basis in the three months to the end of July from a year earlier, while pre-tax profit was up 136% on a like-for-like basis. The results reflect continued improvement in the US, with the company's subsidiary, Sunbelt, seeing a 21% rise in rental revenue to $328m, following the ongoing structural change in the US rental market. Chief executive Geoff Drabble said: "Together with our ongoing improvement in both yield and operational efficiency, these trends resulted in a very strong quarter with pre-tax profits of £34m. "August's US rental revenues continued this pattern with growth of 25%. As a result, the board now anticipates a full year result substantially ahead of its previous expectations."Revenue rose from £239.1m to £268.6m, underlying earnings before interest, taxes, depreciation, and amortisation (EBITDA) increased by 20% (CER:29%) from £78.4m to £93.9m, and adjusted pre-tax profit soared 184% (CER: 211%) from £11.9m to £33.8m. Reported profit before tax rose 136% (CER:148%) from £14.0m last year to £33.1m in the first quarter of the current financial year. The group also acknowledged that it had increased its debt after the capital expenditure made to grow and renew its fleet. At 31 July net debt stood at £848m, up from £806m a year earlier, while the ration of net debt to EBITDA eased to 2.8 from 3.1 at the end of July 2010.NR