The 4-VEP Electric Multiple Units were built for outer suburban services in South London and on rural services in Kent, Sussex and Hampshire. First introduced in 1967, the units were mainly built by BR at York, although some of the early vehicles were produced at BR’s Derby Works. Originally numbered 7701-7894, 194 standard four-car sets entered service and were subsequently renumbered into the 30XX and 31XX series in the 1980s to make them TOPS-compliant. Fitted with manual ‘slam doors’ next to every seating row, they were the last rolling stock built to this pattern for BR, the last units being withdrawn in 2005 after a working life of 38 years.