Liquid, at most stages of the production process, is piped at a flow rate of 1 to 1.2 metres a second - fast enough to prevent it leaving a trace in the pipe.

Currently, when a line is changed, for example from one brand of lager to another, water is pumped through in between the two as a marker indicating the start of one line from the finish of the other.

Using the I-pipe to identify where one liquid stops and another starts therefore reduces the number of contacts where a mixing occurs from two to one. This not only saves on this wastage but also time and labour involved in the changeover.

The technology behind the invention is based upon a process of impedance spectroscopy. A pair of electrodes passes a signal through the liquid in the pipe. If the characteristics of the liquid change, the amplitude of the output signal will become out of phase with that of the input signal and the system recognises it.

As the device will recognise any slight change in composition it also acts as a quality control instrument, removing or reducing the need for manual sampling and laboratory analysis.

Spokesman Richard Shaw revealed that "several blue-chip companies" have already started to adopt the technology, but would not disclose which. Kaiku has recently signed an agreement with Bevertech to distributethe I-pipe in Spain, Portugal, Italy, Greece and France.