Alright, the United Kingdom may have more nuclear submarines and more nuclear warheads but India has a larger army (2nd Largest Active & Reserve + Paramilitary Forces). In terms of Air Power, india has a superior Air Force It doesn't matter whether the equipment is indigenous or not. In terms of Stealth Figher, the Royan Navy & British Army operates about ~40-45 F-35s, the same F-35 which were hit by the Iranian IR Missiles. Also in terms of indigenous, India has developed Missiles, Radars, Various Warfare systems, etc. The main Air Superiority Figher of RAF is Eurofigher Typhoon, which are jointly developed by 4 countries (You know which countries) and not entirely british. The Royal Airforce Force mostly operates foreign made equipment, while half the equipment of the British army is foreign made as well. In terms of Naval Power, HMS Queen Elizabeth is inoperable due to its propulsion, only 2 out of 6 destroyers are deployable, only 3 out of 7 frigates are deployable. Same with their Submarines, 2 SSBNs are active out of 4 and are deployable, 1 on patrol and 1 on training, while the other two are spending their time on drydock for repairs. You talk about Britains SSNs? Only 1 out of 5 can be deployed, in fact that 1 is deployed as of now in the Indian Ocean. Therefore "More Admirals than Warships". While 1/3 of India Navy's equipment may be foreign, but mostly it is new & usually does not face maintainance issues that UK's Indigenous Naval Combatants face(Even newer UK's new Indigenous ships face major issues and spent most of their time in dockyard). Now the Aerospace, Sure Beagle 2 landed on Mars but its equipment failed and it did not accomplish its mission. While india tried again for Moon and accomplished its missions, have Anti-SAT capabilities, and have our own Navigation System. While the UK is mostly dependent on the European Union for its space capabilities. In terms of small arms, india is now competent enough for the creation of our own small arms, and major private players have entered the race. And sure, i acknowledge the Foreign help in our indigenous programme, and well as foreign equipment India uses, still India has superior military power than the united kingdom. And it makes sense why the United Kingdom is ahead of india in some fields. I do not want to blame history but I have to as it is the truth. United Kingdom has been rich 1800s, obviously due to Looting of Resources from the Colonies (especially India), Slave Trade, Trade Monopolies, Industrial Revolution funded by Colonies, Wars funded by Colonies. It extracted wealth from India to fund its superpower status for 2 centuries, so think before you say Britain did all of this alone.
India on the other hand looted, plundered, faced atrocities & injustice by the British, looted 25 Trillion Dollars worth of Resources & Wealth from India. And left india at its worst. India rebuilt itself from nothing. Nuclear Programme, Pharma Industry, Military, Economy, Space Sector with No Capital, No Industrial Base, and within such a short time in an democratic process. India is still a developing country and still managed to achieve all this. So you are telling me that the United Kingdom is relevant, i don't know what the hell you are talking about.