Written constitution is necessary for a number of factors. These have been discussed below:
1) In a written constitution, the possibilities of any doubt arising regarding the distribution of power are low. As we already know that in a federal form of government, power is distributed between the union and states, there are chances of feuds regarding power distribution. However, a written constitution helps a federal country to overcome all such issues.
2) For clear demarcation of powers between the legislature, executive and judiciary, written constitution is the best. It lays proper written principles guiding the distribution of functions.
3) In a country of diversity, a written constitution is nothing less than the guardian of human or fundamental rights of the people.