New battles loom over grammar schools
Grammar schools in England are small in number - there are just 164 - and Kent's decision to allow one to expand onto a different site could signal a turning point for them.
They inspire a lot of passion - both for and against - and this decision has reignited a fierce debate about state schools selecting children on academic ability.
The law bans any building of new grammar schools in England.
Opponents say grammars are socially divisive - sifting children in to "sheep and goats" at 11 through the 11-plus exam, which they have to pass to get a place, and that other schools around grammars suffer.
They say money plays an important part in securing a place at one because of the coaching needed to get children through the test.
Recent figures from the Department for Education show that the proportion of children in grammar schools eligible for free school meals is low - 2.4% - compared with a national average of about 16%.
Supporters of the schools say they are beacons of excellence which help children achieve their potential - and that academically bright pupils are best taught together.
They say they are vehicles for social mobility and more children should have the chance to go to them and they should be allowed to expand further.Rising numbers
Most grammar schools in England were closed in the 1960s and 70s in a shift towards comprehensives and, in 1998, Labour banned the building of any new grammars.
But while there have been no new schools, there have been more places at existing grammar schools as they have expanded on their land.
The Department for Education says numbers of places have risen by 32,000 since then.
Latest figures suggest there are nearly 162,000 children in state-funded academically-selective schools - another way of describing grammar school in England. That equates to about 4.5% of pupils.
About 15 of the 152 English local authorities have fully selective secondary systems - another 21 have some fully selective secondary schools.Catholic bishops
Scotland and Wales do not have grammar schools, but there are 68 in Northern Ireland. They are controversial here too.
The education department scrapped the official secondary transfer test - the 11-plus - three years ago but schools came up with their own versions and academic selection continues.
Catholic bishops have been trying to convince Catholic grammar schools to give up academic selection and the latest plan is for it to be phased out.
The issue is politically sensitive in England and Northern Ireland.
In 2007, David Cameron risked a backbench rebellion when he dropped the party's earlier pledge to build more grammar schools - and have "a grammar in every town" - as he sought to modernise the party.
As Conservative backbenchers attacked the move, Mr Cameron told a Westminster press conference there was a "fantasy element" to the debate, saying the Conservatives had not built new grammars during 18 years in power.
The old Tory policy had been "a chain around our necks", he said.
Graham Brady, a Tory MP and ex-grammar school pupil, quit his front-bench post over the issue.
Labour opposed academic selection but did not abolish any grammars during its years in power.
Instead they set up a mechanism where local parents could push for a school's closure through a ballot. Only one ballot was held - in Ripon, North Yorkshire - but opponents of grammar schools lost.
Now, with the academies programme - which removes schools from the wing of local authorities - and changes to the admissions code, the way is becoming more open for grammars to expand.
Many grammars have converted to academies in England - 119 of the 164 according to figures released earlier this month.
Some say Education Secretary Michael Gove has produced an "elegant political solution" - critics call it a "backdoor expansion".