It hardly even seems to count as news: the German discounters continue to make strides in the UK. The trend has been in evidence for years now, as a tight focus on price and improved ranging enable Aldi and Lidl to continue to win shoppers in their droves. This week's announcement that Aldi plans to invest heavily in the market should be viewed as a signal of intent. The Germans are coming - and their advance is likely to put even more pressure on pricing for food makers. Katy Askew reports.