Mapeley, the listed property owner and manager, suffered a 13% fall in net asset value in the first half of the year.

The fall to 1617p a share came after a 4.7% decline in the value of its freehold portfolio. The fall in the second quarter was 2.3%.

Mapeley’s freehold portfolio fell by 5.6% in the six months to £940.8m after a 45 basis point rise in the yield to 8.1%.

It saw similar falls in the value of the freehold properties it owns in its two large outsourcing contracts, HM Revenue & Customs and Abbey.

The company’s funds from operation, a measure of cash flow which Mapeley uses to gauge its operating performance, was more than double the figure in the same period last year, rising from 94p to 214p a share, or £63.1m.

Excluding one-off asset management receipts in the first quarter funds from operation were 109p a share. An interim dividend of 47p a share is being paid.

Chief executive Jamie Hopkins acknowledged that market conditions ‘remain challenging’ but said he expected Mapeley ‘to perform robustly’.

He added: ‘Our business is underpinned by strong income streams and long term relationships with our clients. 92% of our income is from government and investment grade corporates and our average lease length is 10 years.’