Tower Hamlets has been told to “urgently review” its resident complaints process after being accused of obstructing investigations.

The Local Government and Social Care Ombudsman, which probes allegations against local authorities, said delays were a "significant theme" at the council with "contacts not being responded to, correspondence seemingly going missing and agreements not being implemented".

In two cases the council had to be threatened with a witness summons because of the excessive delays.

"This is an unusual action that should never be necessary," Ombudsman Michael King said.

"Delay merely aggravates injustice to complainants and can erode confidence in the complaints process. I call on the council to urgently review its complaint handling."

The Ombudsman upheld 75 per cent of complaints against the council between March 2018 and March 2019 - higher than the London average of 63 per cent.

The council was ordered to pay a total of £2,450 to residents for failing to deal with 15 grievances properly.

The majority of complaints were to do with housing and adult care services.

Mr King added: "We have noted on numerous occasions this year that there have been problems with the way [the] council has handled our enquiries.

"In one instance, we made enquiries about a complaint but did not receive a response and chased after a month. The council could not find our initial enquiry and committed to a quick response after it had been resent, but it then had to be chased again when the information was not provided. Eventually, we had to threaten a witness summons before we received all the requested information. "The problems continue throughout the complaint process; we had to chase [the] council five times to confirm compliance with a remedy that had been recommended and agreed to. The remedy was confirmed after four months, rather than the six weeks the council had agreed to."

A Tower Hamlets council spokesman said: "We accepted fully the resolution proposed by the Ombudsman on two cases however there were some processing delays in completing them. We have now put in place measures to resolve such cases more quickly in future."