Johnson Matthey’s interim pre-tax profits rose 15 per cent to over £120m as it reaped the benefits of growing demand for heavy duty diesel (HDD) catalysts and particulate filters.

The group predicted that second-half profit growth would be in line with the first half on the back of new auto catalyst capacity and HDD sales to truck makers in the US. Metals trading earnings growth will be less strong because of a particularly strong equivalent period in 2006.