The blue-chip FTSE 100 (.FTSE) fell 0.4%, while the mid-cap FTSE 250 (.FTMC) was down 0.8%, as of 0820 GMT.
Data showed Britain now has Western Europe's highest rate of consumer price inflation, after a weaker-than-expected fall in March to 10.1% from February's 10.4%.
The FTSE 100 clocked its longest winning streak since December 2020 on Tuesday, buoyed by defensive and commodity-linked stocks.
Food, beverages and tobacco sector (.FTUB4510) was a bright spot, up 0.8% on the heels of sticky inflation numbers.
Leading losses on the FTSE 250 was Liontrust Asset Management Plc (LIO.L), down 5.5% as the asset manager reported significant quarterly net outflows.