WSP confirmed the deal in a Stock Exchange announcement this morning.

The takeover at 435p a share represents a 67% premium on WSP’s closing share price on the last full day of trading.

Genivar is a smaller company than WSP employing 5,500 staff compared to WSP’s 9,000 across 30 countries.

Genivar said it did not expect any “significant” staff cuts following the merger.

The takeover announcement stated: “As the footprints of the two groups have limited geographic and client overlap and based on current economic conditions, it is not anticipated that there will be any significant reductions in WSP headcount as a result of the merger.

“However, the combined entity will continue to look for operational efficiencies and to react to market conditions which may involve reductions in headcount in the ordinary course of business.”

Latest results from WSP show the firm made a pre-tax profit of £18.9m for the 12 months to December 2011 on turnover of £713.3m .

WSP has been hit hard by the construction downturn and shed 400 staff last year.

The new WSP and Genivar business will be listed on the Toronto Stock Exchange and WSP chief executive officer Christopher Cole will become executive chairman of the new board of directors.

WSP finance director is expected to leave the group at the end of this year along with all existing non-executive directors.

The new operation will trade under the combined WSP Genivar name.

Cole said: “WSP is a successful global multi-disciplinary professional services consultancy with stated strategic ambitions to diversify and grow.

“Whilst reviewing carefully our options to best achieve this aim, an exceptional opportunity has arisen for WSP to merge with Genivar, a similarly ambitious entrepreneurial yet complementary Canadian consultancy.

“I believe this transaction will provide WSP, our staff and our clients with enhanced opportunities and the combined entity will achieve increased prominence in the global markets in which we work.

“This recommended transaction provides WSP shareholders with cash at an offer price which recognises WSP’s underlying value.”

Pierre Shoiry, President and Chief Executive Officer of Genivar said: “This landmark transaction is an important milestone in the history of Genivar.

“We are very excited to join forces with WSP and have Chris Cole become Executive Chairman of the Board of Directors upon completion of the merger.

“Genivar and WSP are highly compatible in terms of culture and strategic objectives. They are both pure play consulting firms, sharing similar values with respect to people, clients and teamwork.

“We believe that the combination provides a unique opportunity for our clients, employees and shareholders to benefit from the global scale and breadth of services offered by the combined entity.

“Through the combination of our firms, we are creating one of the world’s leading professional services firms.

“Moreover, our firms are complementary with limited geographical overlap, combining talented teams to enhance the leadership and expertise of the global organisation.”