MORE than 60 years ago it took a one-tonne computer the size of a room to run a simple mathematics program, but now United Kingdom computer scientists have "shrunk" it to make it available on your mobile.

Designed and built at the University of Manchester, north-west England, the renowned "Baby" computer was the first of its kind capable of storing information in its memory, changing the face of computing and modern society for ever.

In June 1948 the machine - which was built using spare parts from Spitfire fighter-plane radios and old post-office racks - made history by successfully running a simple routine to determine the highest factor of a number.

"Baby", or to give it its proper name: Small Scale Experimental Machine, was the first to contain memory that could store a program.

The room-size computer's ability to carry out different tasks - without having to be rebuilt - has led some to describe it as the "first modern personal computer". Using only 128 bytes of memory, it successfully ran its first set of instructions, to determine the highest factor of a number, in 1948.

Baby was the successor to machines such as the United States' Eniac and the UK's Colossus. Eniac was built to calculate the trajectory of shells for the US army. Colossus was used to decrypt messages from the German high command during the second world war.

Both computers were able to be reprogrammed but this could involve days of rewiring. Baby was designed to overcome this limitation.

It took 3.5 kilowatt - the equivalent of a domestic, electric room heater going at full force - to power the gigantic Baby. Now, Dr Andrew Robinson from the School of Computer Science at Manchester University has written an application for today's phones that does exactly the same thing.

Mobile users can download the free application from www.d60.org.uk - complete with authentic green screen - and see how many times faster the tiny computer in their pocket performs than the big old Baby. It should run on any phone that supports Java.

Dr Robinson said: "Since mobiles run off batteries, the computers inside them must be extremely energy efficient - much more so than the original Baby used in 1948. To handle the needs of the latest phones with mobile Internet, music players and cameras, they need much more computing power too.

"Although the list of devices containing computers is almost endless, fundamentally they all operate on the same principle which can be traced back over 60 years to the Baby. This application demonstrates how computers were embedded into our everyday lives and how computational performance has increased while their size and energy have decreased," he added.

At the recent Manchester Science Festival, the application was very popular with schoolchildren who were competing to see who can run the program the fastest.

The application was written as part of a public outreach project funded by the Engineering & Physical Sciences Research Council (EPSRC). Manchester Science Festival included more than 150 exciting science, engineering, technology, engineering and maths events for families and adults in venues across Greater Manchester.

The festival brought together universities, organisations and key cultural partners from across the region. It was coordinated by the Museum of Science & Industry and supported by the Northwest Regional Development Agency and the Siemens electronics group.