Recently there was a petition started to ban balloons and sky/Chinese lantern releases. It achieved nearly 27 thousand signatures.
The government has responded with a big fat no. DEFRA says:
The Government considers the current regulatory regime, supported by existing information and guidance, is effective and proportionate.
There is no evidence to suggest that the 2013 study of the risks posed by sky lanterns and helium balloons on livestock and the environment needs to be updated at present.
On land, balloon litter is relatively uncommon, and is not among the top 20 most commonly found types of litter. On beaches, balloons are not in the top ten items of beach litter assessed by the Marine Conservation Society.
Any action must therefore be proportionate to the level of risk. Voluntary actions and initiatives to raise awareness of risks have been effective. The Government has been taking forward a series of non-regulatory measures, aimed at minimising the risks associated with sky lanterns and helium balloons and driving up safety standards, and people are becoming more aware of the risks. Initiatives include a voluntary code of practice for sky lanterns to ensure they are manufactured to be safe and are sold responsibly. The National Association of Balloon Artists and Suppliers, the trade association for the balloon industry, has also published a code of conduct on balloon releases. Moreover, local councils are using existing powers to restrict or regulate the use of lanterns on council-owned land.