Sinhala Only is the Official language of Sri Lanka as it was never repealed. The Tamil Official language legislation has not been implemented.

In 1956 The LSSP leaders warned the Government that Only ONE Official language will create TWO countries and TWO Official languages will help to remain as ONE country, Ceylon.

S`pore has FOUR Official languages and peace and harmony and prosperity.
Sri Lankan Constition as it stands today states in Chapter 4, Clause 18 that
[CHAPTER IV - LANGUAGE

Official Language.

18. 3((1 )) The Official Language of Sri Lanka shall be Sinhala.

4[(2) Tamil shall also be an official language.

(3) English shall be the link language.

(4) Parliament shall by law provide for the implementation of the provisions of this Chapter).

Citizenship Act of 1949 disenfranchised the upcountry Tamils on the ground that their GRAND fathers were NOT born in Sri Lanka.

Ceylon got independence in 1948. It was NOT a colony then.

National Languages.

19. The National Languages of Sri Lanka shall be Sinhala and Tamil. ]

It does clearly say first that Sinhala shall be the official language, instead of Sinhala and Tamils shall be the official languages. more importantly the Sinhala Only Act of 1956 has not been repealed at any time, which over rules any legislation unless it is repealed.

D E W Gunasekara made it clear in an interview to Dily News that Tamil language legislation had not been implemented though under Indo-Lanka Accord it was passed in 1987.

Further, last June the govt paper printed the following which is quite obvious to people with average intelligence:
(LeN-June 29, 6.10 pm) A proposal to make Tamil a national language, one of the root causes that gave rise to the protracted ethnic problem, has been presented to the Cabinet by Constitutional Affairs Minister Dew Gunasekara and granted approval by the cabinet.

Under the 13th amendment introduced in 1987 the official language should be made trilingual, but the non-implementation of it is a violation of the constitution, Gunasekara told today`s Cabinet press briefing.

A decision has been taken to implement the proposal from tomorrow itself and making it mandatory for the public sector employee to have knowledge in Tamil, the Minister explained.

After 21 years of legislating the govt says there will be `jam tomorrow`, well we can hopefully wait for another 21 years for it to be implemented.