Robert Boag is to step down after six years running the UK's biggest property investment trust for Ignis in Glasgow, months after the takeover by Standard Life Investments.

Mr Boag, 50, said he had no plans as yet after handing over the £1.2billion UK Commercial Property Trust in April to SLI's Will Fulton, manager of Standard Life Heritage With Profits Fund's £2.3bn real estate portfolio for the last four years

Analysts at Numis Securities suggested the move might pave the way for a merger with SLI's £277m Property Income Trust, which had made a five-year return of 89.5per cent compared with the Ignis trust's 57.6per cent under Mr Boag, and had a higher yield.

The UK Commercial Property Trust shares however are trading at a 12per cent premium to asset value against 5per cent for the SLI trust.

Chairman Christopher Hill said the board was "sorry that Robert Boag has decided to seek other opportunities", adding that "much of the success of the company has resulted from his conscientious approach and patient leadership".

He went on: "Having overseen the successful transition of the company's portfolio onto SLI's platform, Mr Boag will leave SLI at the end of April 2015. Until then he and Mr Fulton will work closely together in order to achieve a smooth handover of property management."

Mr Boag said: "I genuinely want to take a break, that is the intention. Circumstances change and you respond to them and what you want to do." The demise of Ignis had been "a factor", he said, though not particularly the move from Glasgow to Edinburgh.

He was commenting on another strong year for the trust which hiked net asset value by 18.4per cent in 2014, against 17.4per cent for the property sector index. Its key move was into Aberdeen, investing £48.7m in the Gateway project, in a deal tied up a few months before the oil price went into freefall.

Mr Boag said he was "still very comfortable with the acquisition" given the location, tenant profile and covenants, and some fixed rental uplifts, though he admitted the downturn might have an effect on short-term rental growth in Aberdeen.

He said the trust had continued to concentrate on generating income, focusing on long leases and strong covenants, and benefiting from signs of real growth coming through in the south-east. He was particularly pleased that voids had come down to 2.6per cent at the year end, due to an improvement in the market rather than disposals, one of the trust's lowest ever figures and way below the sector average of 6.8per cent.

"I am sad to leave the team and what is a very exciting company but I think there are lots of things to do and the company is in very good shape," Mr Boag said. The trust had £63.4m in cash at the year end and was due £49.4m from sales, which meant it had "significant resources available for prime, revenue-focused acquisitions and asset management initiatives", the company statement said.

Mr Hill added: "We are confident that the transfer of management and administration is substantially complete and the board is reassured by the depth of resource provided by SLI."