Capita Symonds has completed the acquisition of architect Ruddle Wilkinson, making the multidisciplinary consultant the second-biggest architect in the UK.

Ruddle Wilkinson will become Capita Ruddle Wilkinson and will sit alongside Capita Percy Thomas to create a practice with more than 200 qualified architects and an expected turnover of £30m.

Ruddle Wilkinson is framework design consultant to BAA, Tube Lines, Network Rail, Barnet council in north London and Hatfield & Welwyn council in Hertfordshire. It also has preferred architect status with Ikea, Marks & Spencer, Royal Bank of Scotland, Capital and Regional and Redrow Homes.

The acquisition is the first of a series in what is expected to be a summer of expansion at Capita Symonds. The firm refused to reveal the cost of the acquisition.

Rob Firth, head of architecture at Capita Percy Thomas, said: "Ruddle Wilkinson is a highly respected practice with a wide range of blue chip clients in key sectors where, historically, we have not been represented.