The UK’s benchmark FTSE 100 index fell on Wednesday, dragged by healthcare shares after GSK warned of lower annual vaccine sales, while investors awaited the current government’s first budget that is expected to see biggest tax hikes in 30 years.

The blue-chip FTSE 100 slipped 0.5%, as of 0850 GMT, while the midcap FTSE 250 was flat.

All eyes will be on Britain’s new Finance Minister Rachel Reeves, as she will announce what may be the biggest tax hikes in three decades in a bid to fix the country’s sagging public services, alongside billions of pounds of extra borrowing to overhaul the economy.

The UK’s benchmark 10-year bond yield fell to 4.264% ahead of the budget presentation scheduled for 1230 GMT.

GSK dropped 3.5%, after the drugmaker warned that its vaccine sales would fall this year, after weaker-than-expected sales for its respiratory syncytial virus and shingles vaccines in the third quarter.

The drugmaker pushed the pharma and biotech sector 1% lower. Beverages was the worst hit among sectors, down 1.5%, with Diageo falling 1.7%.

Shares of the UK-listed spirits maker were pressured by a 16.5% slump in Italy’s Campari, after the Italian spirits group missed analysts’ third-quarter earnings expectations.

Aerospace and defence stocks were down 0.9%, led by a 1.9% drop in BAE Systems, after a huge blaze broke out in the early hours at its shipyard that builds Britain’s nuclear submarines but there is no major risk from the incident.

London stocks climb, energy shares keep gains in check

Among other movers, Glencore rose 1.8% as it reported lower copper, cobalt, zinc, nickel and thermal coal production for the first nine months but reiterated it expected its trading profits to reach the high end of its long-term range at up to $3.5 billion.