Johnson Matthey said Wednesday it expected operating profit growth toward the upper end of guidance after revealing first-half profits rose by nearly a fifth driven by 'strong' growth in its clean air division.

'We now expect growth in operating performance at constant rates towards the upper end of our previous guidance of mid to high single digit grow,' the company said.

In the six ended 30 September, pre-tax profits increased 19% to £244m and revenues rose 10% to £7.11bn.

Continued strength in Clean Air was with sales up 11%, well ahead of global vehicle production, driven by double digit growth in both light and heavy duty.

At current foreign exchange rates, translational foreign exchange movements for the year ending 31st March 2019 were expected to benefit sales and underlying operating profit by £1m and £2m, respectively, the company said.

The company declared an interim dividend of 23.25p, up 7% from a year earlier.

'Clean Air continues to grow strongly driven by our diesel share gains in light duty Europe which are coming through as planned. Heavy duty is also performing well, supported by strength in the Class 8 truck market in the US,' said Robert MacLeod, Chief Executive.

'Efficient Natural Resources saw good sales growth and margin improvement, and Health traded in line with our first half expectations. We remain on track with our plans to commercialise eLNOTM, our next generation battery material. Customer feedback remains positive and, in July, the board approved the initial investment in our first commercial plant.'