No, you cannot enter Romania soly based on a United Kingdom residence permit as an Indian citizen.
If you don't have a multi (or an unused dual) entry Schengen Visa, you will require a Romanian Visa.
Ministry of Foreign Affairs of Romania
VI. Do I need a visa?
Please consult the list of states whose citizens (annex 1), holders of simple passports, are required a visa upon entry on the Romanian territory.
Please consult the list of states whose citizens (annex 2), holders of simple passports, are not required a visa to travel to Romania.
Categories of third-state nationals also exempt from the requirement to be in possession of a Romanian short-stay visa are:
- Holders of biometric passports, nationals of the following states:
- the Republic of Moldova;
- the Former Yugoslav Republic of Macedonia;
- the Republic of Serbia, except for the passports issued by the Serbian Coordination Division (in Serbian: Koordinaciona uprava);
- the Republic of Montenegro (the non-biometric passports issued by this state are no longer valid);
- the Georgia
- the Ukraine
Holders of Schengen visas with two or multiple entries, national visas or residence permits issued by Schengen Member States.
Starting July 11, 2014, in keeping with the provisions of Decision No 565/2014/EU, Romania acknowledges as being equivalent to its own national visas, for transit and for stays up to 90 days per period of 180 days the following:
- The two or multiple entry short-stay visa issued by a Schengen member state;
- The limited territorial validity visa issued by a Schengen member state;
- The short-stay visa issued by Bulgaria, Cyprus or Croatia;
- The long-stay visa issued by a Schengen member state;
- The long-stay visa issued by Bulgaria, Cyprus or Croatia;
- The residence permit issued by a Schengen member state;
- The residence permit issued by Bulgaria, Cyprus or Croatia
- The long-term resident's EC residence permit (the validity of which is of 5 years or more) issued by a member state of the European Union.
Attention! The number of entries as well as the right of stay established as per the Schengen visas must not have been exhausted. The right of stay on the territory of Romania shall not exceed the right of stay granted as per the visas/residence permits issued by the Schengen Member States.
The statement made at the Visa Traveler:
UK residence permit should have been granted for 5 or more years
does not seemed to be confirmed by the Ministry of Foreign Affairs of Romania text.
The Long-term resident (European Union) is a special residence permit type issued by some EU Member states and is not the same as a permanent residence permit which is often (but not always) issued after 5 years of residence.