An art teacher faces a lengthy prison sentence after he admitted having sex with a 15-year-old pupil.
Ian Blott, 54, of Church Lane, Thwing, East Yorkshire, had an "intense" two-and-a-half-year relationship with the girl, Hull Crown Court heard.
The married father-of-two initially faced 22 counts relating to the affair but pleaded guilty to four specimen charges on Monday.
The case was adjourned for the preparation of pre-sentence reports.
Blott admitted two charges of sexual activity with a child under 18 by a person in a position of trust between May 2004 and October 2005.
'Serious sentence'
He also admitted two charges of abusing a position of trust between April 2003 and April 2004.
The court was told the sexual activity took place on school premises, outside school hours and during school trips.
Judge John Dowse told Blott: "You know the inevitable consequences of these guilty pleas is a sentence of imprisonment.
"These are serious offences and command a serious sentence."
Blott, who attended court with his wife, was given conditional bail and will be sentenced at a date to be fixed.