Leave To Remain

Leave to Remain is where a further period of leave is sought under the Immigration Rules or on a discretionary basis.

Marriage/Civil Partnership or Unmarried partners
Whether you are married, in a civil partnership or an unmarried partner, you must apply for Further Leave to Remain under Appendix FM of the Immigration Rules. Your partner must be British, settled in the UK or in the UK with refugee leave or humanitarian protection to qualify, in addition, your partner must meet the minimum income threshold, currently set at £18,600, either though income or savings.
 

Article 8 of the European Convention on Human Rights
Further Leave to Remain applications can be made on a private life basis, as a partner or as a parent. Article 8 has been codified within the Immigration Rules under Appendix FM; therefore, any such applications are now made within the scope of the Immigration Rules.