Before 9 July 2012 it was possible to grant long residence after a period of 14 years continuous residence, but that provision was removed by changes to the Immigration Rules on that date. However, a person granted an extension of stay following an application made before 9 July 2012 can still be considered under the rules in force before that date. This means a person granted leave to remain on the basis of 14 years residence in the UK can still be granted ILR once the requirements are met.
Although the automatic 14 years long residence rule has been abolished, paragraph 276D of the Rules does allow for a person to be granted leave to remain on the grounds of ‘private life’ on the basis of long residence in the UK. If you have overstayed you need to look at your circumstances in more detail. For instance: Are you in a relationship with a British or EEA national? Do have a child who has lived in the UK for more than 5 years? Would your life be in danger if you were forced to return to your country?
The 10 year lawful long residence rule still applies, for instance where a student has been legally studying in the UK for 10 years and has no criminal convictions or civil judgments such as County Court Judgments (CCJ).
A CCJ or conviction for not paying your fare on the train could come back to haunt you when making an immigration application for FLR, ILR or marriage – especially if they are not disclosed on the application.
Each case is different and you should seek advice from a qualified immigration adviser who has dealt with applications from overstayers, ‘outside the rule’ cases and human rights article 8 appeal. If you in a relationship or have a child with an EEA national you may apply under more favourable EEA rules.
Read this if you haven't already. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/426432/Long_Residence_v13.pdf