Fake Irish: A borderline example with the Connor family. While Michelle, Liam and Paul were presumably reared in England, they were born to Irish parents and seem to have kept close contact with Ireland (their parents returned to Dublin to live). Of the three, only the actor playing Paul had any known Irish ancestry and even his parents were English-born.
Tracy Barlow. Played by various actors, with Dawn Acton and Kate Ford being one of the best-known.
Tracy's step-brother Peter has been played by six different actors. One even reappeared recently as a completely different character (Kirsty's father).
Most of the characters introduced as children.
Nick Tilsley. Twice, and both times as an adult.
Averted with Chesney Brown — Sam Aston has played the character from a child to an adult.
Post-Script Season: Probably the ultimate example — it has essentially been on a series of postscript seasons since 1961. It was originally intended to be thirteen episodes long, with Coronation Street bulldozed in a Made-for-TV Movie. However, it proved so popular that a new series was commissioned, and it's been broadcasting more or less continuously to the present day.
Averted with William Roache (Ken Barlow) & Michael LeVell (Kevin Webster) - both characters were written off the show whilst their actors were awaiting trial for sexual offences. Both actors were found not guilty, allowing the show to bring them back to the show.
Chris Fountain (Tommy Duckworth) was abruptly fired after a homemade rap video where he sang about rape was discovered online.
Tina O'Brien (Sarah Louise Platt) dated Bruno Langley (Todd Grimshaw), the couple splitting up before their characters began dating.
She then began dating Ryan Thomas, who plays Jason Grimshaw, Todd's brother and Sarah Louise's future husband.
A more successful pairing is between Alan Halsall, who plays Tyrone Dobbs, and former Corrie actress Lucy-Jo Hudson, who played Katy Harris from 2002-2005, who have been married since 2009 and welcomed a baby girl four years later.
Upon both Tracy and Peter's returns in the early 2000s, there were talks for them to become involved with one another and Tracy to become pregnant as a result of the affair. This, thankfully, never came about, due to some very obvious reasons.
Also, there was supposed to be a conclusion to the Maya Sharma storyline involving a trial against her, but was left unresolved due to some personal reasons involving Jimmi Harkishin, who plays Dev Alahan.