For a company that boasts a high level of Customer Service, Transport for London is shambles internally. There is a ridiculous level of red tape and favoritism resulting in huge pay gaps from one band to the next. Promotions are handed based on connections rather than skill and proactive efforts to get yourself recognized are ignored as you identify yourself as a potential threat to senior management through job competition.
As a non-permanent employee you also get no benefits what-so-ever. Compared to completely free travel, better healthcare, private pensions and even personal loan options for all permanent staff, non-permanent members get none of the above.
Unbalanced pay, zero promotion prospects, favoritism based on connections, high risk of job loss if you speak up.