you seriously need some education buddy...
around 1700,it was India and China who was accounted for 60%-70% of world's GDP.during colonial period,our economy was declined severely.while India shared over 22% GDP of world in 1700,it was only shared only 3.8% of world GDP in 1951.so,your so called "Econy flourish during British Period" is wet dream.and here is record of Indian GDP since 1951.....
Financial year GDP of India at factor cost (in percent)
1951-52 2.3
1952-53 2.8
1953-54 6.1
1954-55 4.2
1955-56 2.6
1956-57 5.7
1957-58 -1.2
1958-59 7.6
1959-60 2.2
1960-61 7.1
1961-62 3.1
1962-63 2.1
1963-64 5.1
1964-65 7.6
1965-66 -3.7
1966-67 1
1967-68 8.1
1968-69 2.6
1969-70 6.5
1970-71 5
1971-72 1
1972-73 -0.3
1973-74 4.6
1974-75 1.2
1975-76 9
1976-77 1.2
1977-78 7.5
1978-79 5.5
1979-80 -5.2
1980-81 7.2
1981-82 6
1982-83 3.1
1983-84 7.7
1984-85 4.3
1985-86 4.5
1986-87 4.3
1987-88 3.8
1988-89 10.5
1989-90 6.7
1990-91 5.6
1991-92 1.3
1992-93 5.1
1993-94 5.9
1994-95 7.3
1995-96 7.3
1996-97 7.8
1997-98 4.8
1998-99 6.5
1999-2000 6.1
2000-01 4.4
2001-02 5.8
2002-03 3.8
2003-04 8.5
2005-06
2004-05 7.5
2005-06 9
2006-07 9.2
2007-08 9.8
2008-09 3.9
2009-10 8.2
2010-11 9.6
2011-12 6.9
now if you use PPP as scale,well...I can post you data of past few years...
List of countries by past and future GDP (PPP) per capita - Wikipedia, the free encyclopedia
India's PPP since 1980's only rose..
as for China in the past,China was struggling for centuries due to various political turmoil and its economy was destroyed dur to war as well as civil war.no wonder China will have far better economy as it is far bigger country than India itself.and it strted its liberalisation of economy decade before India did.and India is a democracy,not an autocracy.so,it has to take public opinion in mind before making reform.so,progress is slow.then again,you're an "Expert on India"..you'll know better than me..