"in law and in practice" is correct and usable in written English.
It is used to describe a situation in which something is both legally mandated as well as generally accepted or widely practiced. For example, "Employees have the right to take vacations in law and in practice."
Both in law and in practice.
Amnesty said women in Saudi Arabia face "severe discrimination" in law and in practice.
The only place they are treated well, both in law and in practice, is Israel.
On freedom of belief, he warned: "Religious minorities such as Baha'ís and Christians face violations entrenched in law and in practice.
Their experience illustrates the potential for losses when firms are too slow to respond to changing conditions, both in law and in practice.
But regardless of the differences in law and in practice, both Americans and British are among the worst binge-drinkers in the developed world – and the problems associated with this are manifold.
The answer – alongside creating a more child-friendly public realm – is to enshrine in law and defend in practice all children's right to play out where they live.
Although violence against women and discrimination against women is prevalent in law and in practice/society all around the world, it does not mean that it is inevitable.
All of these factors have led the states to retreat from the death penalty in recent years — in both law and in practice.
To the contrary, in many ways sex discrimination in Yemen is sanctioned both by law and in practice.
The London-based human rights group Amnesty International said in its 2013 report on Iran that women there "faced discrimination in law and practice in relation to marriage and divorce, inheritance, child custody, nationality and international travel".
