Demand in the rental sector has rocketed as people have been unable to buy their own home, either because they cannot raise the deposit needed or meet lenders' toughened borrowing criteria in the difficult economy, which has pushed up the cost of renting.
The Royal Institution of Chartered Surveyors has warned that it is currently possible for people to set up a lettings agency without appropriate qualifications, knowledge or understanding of the rental process and it is not compulsory for them to conform to codes of conduct.
Several calls have been made for better protections for people living in the private rental sector in recent months, with Shelter reporting in September that almost a quarter of people feel they have been "ripped off" at some point by letting agents' charges.
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The capital's theatres also generate more searches than those in any other city, according to research by Google.
Union officials are expected to meet next week to plan further stoppages if talks fail to resolve the dispute.
Natalie Sharp and Christine Bicknell appeared in court over an alleged incident at a Lidl superstore in Wallington, south London.