In 2016-17, secondary schools in Lancashire handed out 6,224 exclusions to children, the latest Department for Education data shows.
This was a rate of nine exclusions for every 100 pupils, and a 29 per cent increase from 2010-11 when there were just 4,815 exclusions, or seven per 100 pupils.
The National Association of Headteachers said: “School budgets are at breaking point and many interventions for our most vulnerable young people are being cut.”
Paul Whiteman, general secretary of the NAHT, said: “A school’s first duty is the safety of its students, and so school leaders need to retain the autonomy to exclude a violent pupil in order to keep everyone else safe.”
In Lancashire, there were 298 permanent and 5,926 temporary, or fixed-term, exclusions in 2016-17.
Across the country, exclusions have increased by 12 per cent since 2010, climbing from 276,350 to 309,275. The sharpest increase was in permanent exclusions, which have increased by 46 per cent to 6,385.
A Department for Education spokesman said permanent exclusions should only ever be a last resort. He said: “It is still vital that young people who are excluded from school are able to engage with high-quality teaching and education.
“That’s why we have launched a £4m fund which is delivering projects to improve outcomes for children in alternative provision, including pupil referral units.”